1900 


B    3    135    fll? 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


CTVvxAxO        I  T  (^-iVh-A^^LO 


,  BIOLOGY 


A     PLETHYSMOGRAPHIC     STUDY     OF     THE     VASCULAR 
CONDITIONS  DURING  HYPNOTIC  SLEEP. 


A  DISSERTATION  SUBMITTED  TO  THE  BOARD  OF  UNI 

VERS1TY   STUDIES  OF   THE   JOHNS   HOPKINS 

UNIVERSITY  FOR  THE  DEGREE  OF 

DOCTOR  OF  PHILOSOPHY. 

1900. 


BY  ELISHA  CHISHOLM  WALDEN. 


VV3 

BIOLOGY 

LIBRARY 

G 


A     PLETHYSMOGRAPHIC    STUDY    OF    THE    VASCULAR 
CONDITIONS    DURING    HYPNOTIC    SLEEP. 

BY  E.    C.    WALDEN. 
[From  the  Laboratory  of  Physiology  in  the  Johns  Hopkins  University^ 

CONTEXTS. 

Page 

Introduction 124 

Description  of  the  apparatus 125 

Description  of  the  plethysmographic  curves 132 

a.  Normal  curves 133 

b.  Exceptional  curves 137 

c.  Effect  of  suggestion 139 

Description  of  other  phenomena 141 

a.  Blood-pressure  curves 141 

b.  Pulse  rate 144 

c.  Respiration 146 

d.  Temperature 147 

1.  Rectal  temperature 147 

2.  Surface  temperature 148 

Discussion  of  results 149 

a.  Suggested  explanation  of  the  meaning  of  the  plethysmographic  curves  149 

b.  Probable  explanation  of  the  changes  in  the  blood-pressure    ....  155 
Summary  and  general  conclusions 158 


INTRODUCTION. 

THE  principal  object  of  these  experiments  has  been  to  deter- 
mine the  changes  occurring  in  the  volume  of  the  arm  as  a 
consequence  of  hypnotic  sleep  and  suggestion,  and  to  compare  the 
results  so  obtained  with  the  observations  which  have  been  made  by 
the  same  methods  on  normal  sleep.  It  has  been  shown  by  Mosso,1 
Howell,2  and  other  investigators,  by  means  of  the  water  plethysmo- 
graph,  that  the  volume  of  the  arm  is  increased  during  normal  sleep. 
The  same  authors  have  also  shown  that  mental  and  muscular  activity 
cause  a  constriction  of  the  arm.  These  changes  are  assumed  by  How- 
ell  to  be  due  to  vasomotor  changes  in  the  cutaneous  blood  vessels 

1  Mosso:  Ueber  den  Kreislauf  des   Blutes  im  menschlichen  Gehirn,  Berlin, 
1881 ;  Die  Temperatur  des  Gehirns,  Berlin,  1894. 

3  HOWELL  :  Journal  of  experimental  medicine,  1897,  ii,  p.  313. 

L31179 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      125 

and  a  consequent  alteration  in  the  amount  of  blood  flowing  through 
the  peripheral  vessels.  The  present  experiments  have  been  extended 
so  as  to  include  not  only  the  plethysmographic  records,  but  records 
of  the  blood-pressure,  pulse,  respiration,  and  temperature,  as  well. 

DESCRIPTION  OF  THE  APPARATUS. 

The  plethysmograph  used  was  similar  to  that  previously  described 
by  Howell.1  It  consisted  of  a  glass  cylinder  of  sufficient  size  to 
allow  the  hand  and  a  portion  of  the  fore-arm  to  be  inserted  in  it. 
One  end  of  the  cylinder  was  drawn  out  and  w,as  connected  to  one 
arm  of  a  three-way  stop-cock  by  stiff  rubber  tubing.  On  one  side  of 
the  cylinder  there  was  a  small  neck,  into  which  was  fitted  a  piece  of 
glass  tubing  provided  with  a  stop-cock.  This  opening  served  as  an 
escape  for  the  air  while  the  apparatus  was  being  filled  with  water.  The 
two  remaining  arms  of  the  three-way  stop-cock  were  joined,  one  to  the 
recording  apparatus  and  one  to  the  reservoir,  which  contained  water 
for  filling  the  apparatus.  By  turning  the  cock,  the  plethysmograph 
could  be  connected  with  the  recording  apparatus,  the  reservoir,  or 
with  both. 

The  recorder  used  was  the  form  devised  by  Bowditch.2  It  con- 
sisted of  a  test-tube  swung  on  a  spiral  spring  in  such  a  manner  that 
the  height  of  the  water  always  remained  constant,  the  test-tube  being 
pulled  up  by  the  tension  of  the  spring  as  water  was  withdrawn  from 
the  tube,  and  the  spring,  in  turn,  being  stretched  out  as  water  was 
poured  into  the  test-tube.  The  spiral  spring  was  fastened  to  a  short 
vertical  rod,  and  this  was  attached  to  another  longer  vertical  rod  by 
means  of  a  universal  joint.  The  longer  vertical  rod  was  firmly  fast- 
ened to  a  table.  By  means  of  the  universal  joint  the  height  of  the 
test-tube  and  the  tension  of  the  spring  were  very  easily  regulated. 
A  pen  of  thin  paper  was  attached  to  the  test-tube  and  wrote  against 
the  blackened  surface  of  a  drum  kymographion,  which  revolved  once 
in  six  hours.  Two  other  pens  were  arranged  to  write  in  the  same 
vertical  line.  One  of  these  pens  was  connected  with  an  electric 
signal,  in  circuit  with  a  clock,  and  marked  intervals  of  one  minute. 
The  other  pen  was  attached  to  a  lever  and  was  used  to  record  the 
application  of  any  stimulus  that  was  given  to  the  subject,  or  any 
change  that  was  noticed  in  his  condition. 

1  HOWELL:  Journal  of  experimental  medicine,  1897,  ii,  p.  313. 

2  BOWDITCH  :  Proceedings  of  the  American  Academy,  May  14,  1896. 


126  E.  C.  Walden. 

To  keep  the  arm  immovable  in  the  plethysmograph,  the  device 
described  by  Howell1  and  Shields2  was  used.  This  consisted  of  a 
hinged  collar  of  hard  rubber,  which  fitted  around  the  thumb  between 
the  first  and  second  phalangeal  articulations.  This  collar  was  rigidly 
attached  by  a  brass  rod  to  another  collar  of  hard  rubber  which  fitted 
loosely  over  the  fore-arm.  The  outer  circumference  of  this  collar  was 
of  such  a  size  that  it  fitted  snugly  into  the  mouth  of  the  glass  cylin- 
der. The  object  of  this  device  was  to  prevent  the  arm  from  slipping 
farther  into  the  plethysmograph.  To  prevent  the  arm  slipping  out 
of  the  plethysmograph,  the  device  described  by  Shields3  was  used. 
This  consisted  of  two  hinged  hard  rubber  rings.  The  larger  one  of 
these  rings  fitted  around  the  end  of  the  glass  cylinder,  the  other  ring, 
of  just  sufficient  size  to  allow  the  fore-arm  to  pass  through  it,  was 
connected  to  the  first  by  screw  clamps,  so  that  the  smaller  collar 
could  be  pressed  up  against  the  end  of  the  cylinder,  and  in  this  way 
prevented  the  collar  within  the  cylinder  from  being  pulled  out. 

The  plethysmograph  was  swung  from  the  ceiling,  and  was  so 
arranged  that  it  could  be  adjusted  to  any  desired  level.  The  elbow 
was  supported  by  means  of  a  sling,  which  was  fastened  to  the  chain 
holding  the  plethysmograph. 

The  greatest  difficulty  encountered  in  all  plethysmographic  experi- 
ments has  been  to  secure  some  device  whereby  the  arm  could  be  en- 
closed within  the  plethysmograph  in  such  a  manner  as  to  prevent 
leakage  from  the  cylinder,  and  at  the  same  time  to  avoid  compression 
of  the  arm.  The  errors  which  occur  in  either  case  spoil  the  records 
obtained.  The  original  device  employed  by  Mosso,4  consisting  of  a 
rubber  sleeve,  was  not  entirely  satisfactory  when  used  alone,  the 
chief  objection  being  the  difficulty  in  adjusting  the  sleeve  to  the  size 
of  the  arm  of  the  subject  for  each  experiment,  without  causing  undue 
compression  of  the  arm.  The  rubber  sleeve  only  serves  this  purpose 
when  it  is  very  carefully  adjusted  to  the  arm.  A  device  has  been 
used  in  these  experiments  which  can  readily  be  adjusted  to  any  arm 
without  danger  of  either  a  leakage  from  the  instrument  or  a  compression 
of  the  arm.  A  piece  of  heavy  rubber  band  tubing,  fifteen  centimetres 
in  length  and  of  sufficient  diameter  to  allow  it  to  fit  loosely  around 

1  HOWELL:  Journal  of  experimental  medicine,  1897,  ii,  p.  313. 

2  SHIELDS  :  Journal  of  experimental  medicine,  1896,  i,  p.  74. 

3  SHIELDS.  Journal  of  experimental  medicine,  1896,  i,  p.  74. 

4  Mosso :  Ueber  den  Kreislauf  des  Blutes  im  menschlichen  Gehirn,   Berlin, 
1 88 1  ;  Die  Temperatur  des  Gehirns,  Berlin,  1894. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.     1 2  7 

the  fore-arm,  was  drawn  over  the  hand  and  fore-arm,  the  upper  end 
of  the  sleeve  reaching  the  elbow.  A  surgeon's  glove,  of  thin  rubber 
and  provided  with  a  long  sleeve,  was  then  drawn  over  the  hand  and 
the  heavy  rubber  sleeve.  A  second  piece  of  band  tubing,  similar  in 
every  respect  to  the  piece  first  slipped  over  the  fore-arm,  was  then 
pulled  over  the  sleeve  of  the  rubber  glove,  in  such  a  manner  that  the 
thin  rubber  sleeve  was  sandwiched  between  the  two  pieces  of  heavy 
rubber  tubing.  The  thumb  was  next  secured  in  the  holder  used  to  pre- 
vent the  arm  from  slipping  too  far  into  the  cylinder,  and  the  hand  was 
then  thrust  into  the  plethysmograph.  The  upper  ends  of  the  heavy 
rubber  tubing,  between  which  lay  the  thin  rubber  sleeve,  were  then 
inverted  over  the  mouth  of  the  cylinder,  and  were  securely  tied.  The 
hard  rubber  collar  was  next  adjusted  on  the  arm  in  such  a  manner 
that  the  rubber  sleeves  were  tightly  clamped  between  the  inner  collar 
and  the  smaller  one  of  the  collars  on  the  outside  of  the  cylinder,  and 
this  collar  was  then  firmly  fastened  to  the  hard  rubber  ring  encircling 
the  end  of  the  cylinder.  The  rubber  glove  completely  closed  the  open 
end  of  the  glass  cylinder,  so  that  there  was  no  possibility  of  a  leak. 
The  object  of  the  pieces  of  heavy  rubber  band  tubing,  one  on  each 
side  of  the  thin  rubber  sleeve,  was  to  reinforce  the  thin  rubber  at  the 
mouth  of  the  plethysmograph.  Were  it  not  for  this  protection  the 
water  within  the  cylinder  would  affect  the  thin  sleeve,  pushing  it  out, 
and  in  this  way  the  accuracy  of  the  instrument  would  be  destroyed. 
Since  the  rubber  sleeves  used  did  not  bind  the  arm,  there  was  no 
danger  of  compression,  the  arm  being  under  the  same  pressure  it 
would  have  been  were  it  enclosed  in  the  same  volume  of  water  with- 
out the  sleeve  intervening.  The  hand  and  about  nine  centimetres  of 
the  fore-arm  were  enclosed  in  the  thin  rubber  sleeve ;  this  sleeve  was 
forced  snugly  against  the  skin  by  the  water  within  the  instrument, 
the  water  at  the  same  time  forcing  any  air  out  that  might  have  been 
imprisoned  between  the  glove  and  the  arm.  With  this  arrangement  the 
thin  rubber  glove  acted  as  a  second  skin,  allowing  the  arm  and  hand 
to  increase  or  decrease  readily  in  volume,  and  these  changes  in  the 
volume  were  promptly  recorded  by  the  corresponding  outflow  or 
inflow  of  water  from  the  plethysmograph  to  the  hanging  test-tube. 
The  adhesion  of  the  thin  glove  to  the  arm  entirely  prevented  any 
chance  of  air  forcing  its  way  between  the  glove  and  the  skin. 

When  the  subject  was  ready  for  an  experiment,  the  glove  was 
drawn  on  and  the  arm  secured  in  the  plethysmograph.  The  three- 
way  stop-cock  was  turned  so  that  the  plethysmograph  was  placed  in 


p  p  * 

OP 

(   UNIVERSITY 
x.  i~      OF 

77     /**      7T7     7^  >N«*&i-/FORJikt^ 

128  ^.  C .  Walden. 

connection  with  the  reservoir.  As  the  instrument  filled  with  water, 
the  air  within  the  plethysmograph  was  forced  out  through  the  small 
opening  in  the  top  of  the  cylinder.  As  soon  as  the  instrument  was 
filled  with  water,  this  opening  was  closed.  The  water  was  still  forced 
into  the  plethysmograph  from  the  reservoir  until  the  hand  was  under 
considerable  pressure.  This  pressure  was  sufficient  to  force  out  ajiy 
air  that  might  have  remained  between  the  sleeve  and  the  arm,  and  it 
was  also  effective  in  fitting  the  glove  closely  to  the  arm  and  hand. 
When  the  glove  had  been  pressed  down  against  the  hand,  the  stop- 
cock was  turned  so  that  the  plethysmograph  was  placed  in  connec- 
tion with  the  recorder,  the  water  supply  from  the  reservoir  being  shut 
off  at  the  same  time.  Under  these  conditions  water  flowed  from  the 
plethysmograph  to  the  recording  test-tube  until  the  pressure  within 
the  cylinder,  and  consequently  the  pressure  exerted  against  the  arm, 
was  equal  to  the  level  of  the  column  of  water  in  the  test-tube.  If  the 
water  level  in  the  test-tube  was  higher  than  the  level  of  the  cylinder, 
the  arm  in  the  plethysmograph  was  subjected  to  positive  pressure. 
If,  on  the  contrary,  the  cylinder  was  higher  than  the  level  of  the 
water  in  the  test-tube,  the  arm  was  under  negative  pressure.  This 
must  be  avoided,  for,  as  was  shown  by  Shields,1  a  positive  pressure 
on  the  arm  may  cause  a  marked  constriction,  while,  on  the  other 
hand,  negative  pressure  causes  the  arm  to  dilate.  If  the  test-tube 
was  so  arranged  that  the  level  of  the  water  within  it  was  at  the  height 
of  the  middle  of  the  cylinder,  then  the  arm  within  the  cylinder  was 
half  of  it  under  a  slight  negative,  and  half  of  it  under  a  slight  positive 
pressure. 

Records  of  the  blood-pressure  were  taken  by  a  modification  of 
Mosso's  sphygmomanometer.2  The  apparatus  consisted  of  two  glass 
tubes,  one  above  the  other,  and  of  sufficient  size  to  allow  the  fingers 
to  be  easily  inserted.  The  tubes,  which  were  connected  with  each 
other,  were  filled  with  water,  which  placed  the  fingers  under  a  counter 
pressure.  To  prevent  leakage,  the  fingers  were  inserted  into  thin 
rubber  or  membrane  fingers  which  were  securely  fastened  to  the 
cylinders.  Besides  these  thin  fingers,  thin  leather  collars  were  pulled 
over  the  rubber  fingers  to  reinforce  them  and  prevent  the  possibility 
of  bulging  of  the  rubber  when  the  fingers  were  subjected  to  great 
pressure.  The  hand  was  held  in  position  by  a  hard  rubber  collar 
which  fitted  around  the  wrist  and  which  was  secured  to  the  base  sup- 

1  SHIELDS:  Journal  of  experimental  medicine.  1896,  i,  p.  74. 

2  Mosso  :  Archives  italiennes  de  biologic,  1895,  xxiii,  p.  177. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.     129 

porting  the  glass  tubes.  This  prevented  the  fingers  from  slipping 
out  of  the  apparatus  when  pressure  was  applied.  The  pressure  was 
regulated  by  means  of  a  pressure  flask  swung  from  the  ceiling,  and 
so  arranged  that  it  could  be  raised  or  lowered  as  was  desired.  The 
pressure  was  registered  by  a  mercury  manometer  arranged  to  take 
graphic  records. 

The  method  of  determining  the  blood-pressure  by  this  instrument 
was  as  follows :  the  fingers  were  first  inserted  into  the  tubes,  and  the 
hand  secured  in  its  position.  The  pressure  on  the  fingers  was  in- 
creased gradually  by  raising  the  pressure  bottle.  As  the  pressure 
was  increased,  the  amplitude  of  the  pulsations  increased  until  a  cer- 
tain pressure  was  reached ;  any  increase  in  the  pressure  beyond  this 
point  caused  the  pulse  to  diminish  in  amplitude,  the  pulse  being  en- 
tirely obliterated  if  the  pressure  was  raised  to  a  sufficient  height. 
This  point  having  been  reached,  any  decrease  in  the  pressure  was 
followed  by  a  return  of  the  pulse  and  an  increase  in  its  amplitude, 
the  maximal  amplitude  on  decreasing  the  pressure  being  observed  at 
about  the  same  pressure  as  with  the  increasing  pressure.  The  varia- 
tion in  the  maximal  amplitude  of  the  pulsations  on  the  rising  and 
descending  scale  never  amounted  to  more  than  five  millimetres  of 
mercury.  If  before  the  pressure  records  were  taken,  the  pressure 
was  rapidly  raised  and  then  lowered,  the  readings  secured  were  al- 
most the  same  with  both  ascending  and  descending  variations  in  the 
pressure.  It  was  found  that  the  temperature  of  the  water  used  in 
the  instrument  had  a  great  effect  upon  the  amplitude  of  the  pulsa- 
tions. If  the  water  was  cold,  the  amplitude  of  the  pulse  was  very 
small,  and  it  was  with  difficulty  that  the  maximal  pressure  could  be 
distinguished.  When  the  water  used  was-  of  a  higher  temperature 
than  that  of  the  fingers,  the  pulsations  were  markedly  increased  in 
amplitude,  and  the  differences  in  the  amplitude  when  the  fingers  were 
under  different  pressures  were  easily  recognized. 

In  order  to  test  the  accuracy  of  the  principle  of  the  Mosso  sphyg- 
momanometer,  experiments  were  made  upon  dogs.  A  small  mem- 
brane tube,  of  sufficient  size  to  allow  the  carotid  artery  of  a  dog  to 
slip  through  it  easily,  was  fastened  securely  to  one  end  of  a  glass 
tube  8  cm.  long  and  I  cm.  in  diameter.  The  membrane  tube  was 
pushed  into  the  glass  tube  and  was  prevented  from  slipping  out  by 
a  cork  fastened  into  the  end  of  the  tube.  A  small  hole  was  bored 
through  the  centre  of  the  cork,  large  enough  to  allow  the  artery  to 
be  passed  through  it.  The  opposite  end  of  the  glass  tube  was  closed 

9 


3o 


E.  C.  Walden. 


by  a  cork  through  which  a  small  glass  tube  entered  the  cylinder. 
This  tube  was  connected  by  a  glass  "  T"  piece  to  an  ordinary  mer- 
cury manometer  and  to  a  pressure  bottle.  The  carotid  artery  to 
be  experimented  upon  was  exposed  and  carefully  dissected  out 
from  the  tissues  for  a  distance  of  about  eight  centimetres.  It  was 
then  ligated  and  cut  through.  To  the  peripheral  stump  a  strong 
thread  was  attached,  and  this  was  pulled  through  the  cork  and  'the 
membranous  tube,  until  at  least  five  centimetres  of  the  artery  were 
enclosed  within  the  tube.  The  free  end  of  the  artery  and  of  the 
membranous  tube  were  then  tied  securely  together,  in  such  a 
manner  that  there  was  no  leak  when  pressure  was  applied.  The 
artery  and  membrane  tube  enclosing  it  were  held  in  position  in  the 
glass  tube  by  a  thread  tied  to  the  free  end  of  the  artery  and  passed 
out  through  the  cork  at  the  distal  end  of  the  glass  tube.  The  appa- 
ratus was  next  filled  with  water  from  the  pressure  flask.  Even  at 
zero  pressure  pulsations  were  visible  in  the  mercury  manometer,  and, 
as  the  pressure  was  raised,  these  oscillations  of  the  mercury  became 
more  pronounced  until  a  certain  pressure  was  reached,  at  which 
point  the  amplitude  of  the  pulsations  was  maximal.  Any  increase 
or  diminution  in  the  pressure  from  this  point  caused  a  diminution  in 
the  amplitude  of  the  pulsations.  Two  experiments  were  made  with 
this  apparatus,  in  one  of  which  the  right  and  in  the  other  the  left 
carotid  artery  was  fastened  in  the  glass  tube  of  the  sphygmoma- 
nometer.  The  carotid  artery  of  the  opposite  side  was  connected 
in  the  usual  way  with  an  ordinary  mercury  manometer  and  served  as 
a  control  to  the  pressure  observations  made  with  the  sphygmomano- 
meter.  The  results  obtained  in  these  experiments  are  given  below. 

Experiment  1.  —  Length  of  time  during  which  the  observations  were  taken,  48  minutes. 
Sphygmomanometer  on  the  right  carotid. 

Right  Carotid.  Left  Carotid. 

142  mm.  Hg.  150  mm.  Hg. 

140  "      "  148    "      " 
150    "      "  152     "      " 

141  "   "  149  "   " 
136  "   "  144  "   " 
134  "   "  144  "   " 

Average  140.5  mm.  Hg.    Average  147.8  mm.  Hg. 

In  this  experiment  the  pressure  registered  in  the  left  carotid  is  a 
few  millimetres  higher  than  the  pressure  registered  on  the  right  side. 
In  the  following  experiment  the  Sphygmomanometer  was  placed  on 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.     131 

the  left  carotid  and  the  mercury  manometer  was  connected  with  the 
right  carotid  artery.  The  results  of  this  experiment  are  shown  in 
the  following  table : 

Experiment  ^.  —  Period  during  which  the  observations  were  made,  1  hour  and  20 
minutes.  Sphygmomanometer  on  the  left  carotid. 

Right  Carotid.  Left  Carotid. 

153  mm.  Hg.  160  mm.  Hg. 

144  "      "  144  "       " 
139    "      "  143  "      " 
130    "      "  138  "      " 

137  "      "  143  "      " 

138  "      "  140  "      « 

145  "   "  150  "   " 
142  "   "  148  "   " 
128  "   "  132  "   " 
230  "   "  134  "   " 

Average  138.6  mm.  Hg.    Average  143.2  mm.  Hg. 

In  this  experiment  the  greatest  pressure  was  also  recorded  by  the 
instrument  in  the  left  carotid. 

The  temperature  was  registered  by  standard  thermometers,  read- 
ings being  made  every  fifteen  minutes.  The  rectal  temperature  was 
obtained  by  thrusting  a  thermometer  up  the  rectum  about  five 
centimetres.  The  temperature  was  also  taken  of  both  the  arms.  A 
small  mat  of  cotton  was  fastened  loosely  to  the  arm,  and  the  ther- 
mometer was  thrust  between  the  cotton  and  the  skin.  The  cotton 
prevented  the  slight  variations  in  the  room  temperature  from  affect- 
ing the  readings  of  the  thermometer.  The  pulse  was  taken  from  the 
radial  artery,  the  number  of  pulsations  counted  in  one-half  minute 
being  doubled  and  the  result  taken  as  the  number  for  one  minute. 
The  respiratory  rate  was  obtained  by  simply  counting  the  number  of 
respirations  in  one  minute. 

The  subject  for  the  experiment  was  placed  upon  a  bed.  He  was 
allowed  to  rest  from  fifteen  minutes  to  one-half  hour  before  any 
records  were  taken.  The  subject  was  kept  as  quiet  as  possible,  and 
all  unnecessary  noise  on  the  part  of  the  observers  was  avoided. 
When  the  subject  had  rested  a  sufficient  time,  the  readings  were 
begun,  two  or  three  readings  being  taken  before  any  suggestion  was 
given  to  the  subject. 


132  E.  C.  Walden. 

DESCRIPTION  OF  THE  PLETHYSMOGRAPHIC  CURVES. 

Over  twenty-five  experiments  have  been  made  on  hypnotic  sleep 
in  the  present  investigation.  The  plethysmographic  records  ob- 
tained in  the  first  few  experiments  were  not  so  satisfactory  as  were 
the  tracings  obtained  from  the  later  experiments,  owing  to  the  diffi- 
culty encountered  in  so  adjusting  the  rubber  sleeve  to  the  arm  that 
it  neither  compressed  the  skin  veins  nor  allowed  leakage  from  the 
instrument.  Although  the  first  experiments  were  inaccurate  in 
regard  to  the  volume  changes  in  the  arm,  yet  the  general  course  of 
the  curves  was  the  same  as  in  the  later  experiments,  and  hence  these 
tracings  may  be  taken  as  confirmatory  of  the  curves  obtained  later, 
in  which  the  volume  changes  in  the  arm  were  more  accurately 
registered  by  the  recorder. 

The  curves  shown  in  Figs.  I,  2,  and  3  are  the  plethysmographic 
tracings  of  three  experiments  in  this  series,  and  they  show  the  most 
characteristic  changes  noticed  in  a  subject  when  in  perfectly  quiet 
hypnotic  sleep. 

Many  investigators,  among  whom  are  Mosso,1  Howell,2  Shields,3 
and  Kiesow,4  have  shown  that,  in  normal  physiological  conditions, 
the  arm  constantly  undergoes  changes  in  its  volume,  and  that  this 
is  true  no  matter  what  may  be  the  position  of  the  body.  These 
changes  are  usually  small,  but  vary  greatly  in  amplitude,  and  are 
attributable  to  mental  and  sensory  stimuli  acting  upon  the  vaso- 
motor  centres.  The  course  of  the  plethysmographic  curve  from  an 
individual  in  the  normal  waking  state,  care  being  taken  that  all 
muscular  movement  is  absent,  is  in  a  general  horizontal  direction. 
On  this  curve  there  may  appear  rhythmic  variations  due  to  the 
respiratory  movements  and  other  longer,  irregular,  wave-like  varia- 
tions which  probably  depend  upon  rhythmic  changes  in  the  vaso- 
motor  centres.  Besides  these,  the  irregular  variations  due  to  sensory 
and  mental  stimulation,  already  referred  to,  are  more  or  less  abun- 
dant. With  continued  sensory  stimulation  or  mental  activity,  the 
curve  mounts  up  above  the  normal  level,  showing  that  there  has 
been  a  decrease  in  the  volume  of  the  arm.  In  normal  sleep  there  is 

1  Mosso:  Ueber  den  Kreislauf  des  Blutes  im  menschlichen  Gehirn,  Berlin, 
1 88 1  ;  Die  Temperatur  des  Gehirns;  Berlin,  1894. 

2  HOWELL:  Journal  of  experimental  medicine,  1897,  ii,  p.  313. 

3  SHIELDS:  Journal  of  experimental  medicine,  1896,  i,  p.  74. 

4  KIESOW:  Archives  italiennes  de  biologic,  1895,  xxiii,  p.  198. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      133 


a  fall  in  the  curve  which  lasts 
with  variations  as  long  as  the 
sleep  continues ;  this  fall  in 
the  curve  denotes  an  increase 
in  the  volume  of  the  arm. 
In  normal  physiological  con- 
ditions, therefore,  the  course 
of  the  plethysmographic 
curve  varies  under  different 
conditions,  a  rise  in  the  curve 
following  psychical  activity, 
while  normal  sleep  causes  the 
curve  to  sink.  With  this 
summary  of  the  changes 
observed  under  normal 
physiological  conditions,  the 
phenomena  observed  in  hyp- 
nosis may  now  be  described 
in  detail. 

Normal  Curves.  —  Before 
the  hypnotic  suggestion  was 
given  to  the  subject,  the 
curve  was  allowed  to  estab- 
lish its  normal  level  for  the 
recumbent  position.  This 
level  having  been  established, 
suggestion  was  begun.  The 
instant  the  suggestion  of  hyp- 
notic sleep  was  given  to  the 
subject,  there  was  a  pro- 
nounced rise  in  the  curve, 
corresponding  to  a  constric- 
tion of  the  arm,  the  curve 
mounting  upward  for  from 
one  to  ten  minutes.  The 
change  in  the  volume  of  the 
arm  during  this  period  was 
by  no  means  the  same  in  the 
different  experiments,  vary- 
ing, in  round  numbers,  from 


^  .S  *  .SP-c 

or?  _*   LO    Jr     S 


«  JS  -M  •£   § 
•g  °vrt  e  g> 

S    $  -0  '"  J$ 

>      >      4>      C 

o    ^    c    £    S 

S*J3! 

E-  § 


u    +j 


*    o  -5 


M      C      W    S 

•S    B 
o  '£ 


»  s  3 1 « 

«H  to      O      <U 

^^  g^§ 

^     ^*      ^3 

<u    o    t«  "53 

"T3    "*3  2O 


^3     O  "S     «« 

fcJO     O      ^      S    ^ 


e  i •&£     B 

?  f  ^-S  ^  8 

*>    H   -M  ja    °  pQ 

!tif§i 

f  «  £  o-^-g 

CL  ^      >•      £      S 


w  J»    cr  «  -  ^ 
1   S  "2    «    S    e 

S    ,7>    -M    J=l      Si      o 


S     rt     C 

!s-3 


S     KH       g 

O,  K    rt 


*rl!! 


I    ^5 
^  w   2, 


it 


134 


E.  C.  Walden. 


two  to  eight  cubic  centimetres 
for  the  hand  and  that  portion 
of  the  fore-arm  within  the 
plethysmograph.  At  just  what 
point  during  the  suggestion  the 
subject  fell  into  hypnotic  sleep 
it  is  impossible  to  determine. 
That  hypnosis  does  occur 
during  this  rise  is  probable, 
since  the  constriction  of  the 
arm  corresponded,  in  every 
case,  to  the  period  during 
which  the  suggestion  was 
given,  and  as  soon  as  the  sug- 
gestion was  ended,  the  subject 
being  in  hypnotic  sleep,  there 
was  a  fall  in  the  curve.  In 
some  of  the  experiments  this 
fall  was  so  small  that  it  was 
easily  overlooked,  while  in 
other  experiments  there  was  a 
marked  fall  indicating  a  change 
in  the  volume  of  the  hand  and 
fore-arm  of  at  least  ten  cubic 
centimetres.  This  change, 
corresponding  to  a  vascular 
dilatation  of  the  arm,  was  never 
so  rapid  as  the  previous  rise. 
The  time  during  which  the  fall 
continued  varied  greatly  in  the 
several  experiments.  In  some 
cases  it  lasted  but  one  or  two 
minutes,  while  in  other  experi- 
ments the  curve  continued  to 
sink  for  more  than  two  hours. 
The  fall  in  the  curve  differed 
from  the  previous  rise  in 
another  particular.  The  rise 
was  as  a  rule  continuous,  while 
the  fall  was  broken  and  often 
concealed  for  some  minutes  by 


Study  of  Vascular  Conditions  ditring  Hypnotic  Sleep.      135 


irregular  oscillations  which 
occurred  in  the  path  of  the 
tracing.       These    variations 
correspond    in    every    par- 
ticular  to   the    sharp    vaso- 
motor  variations  noticed  in 
all    plethysmograp  hie 
tracings   in   normal   physio- 
logical conditions,  and  hence 
they  are  probably  due  to  the 
same  causes.     After  having 
reached  its  lowest  point,  the 
curve  usually  began  to  show 
a    steady    rise,    which    was 
quite  gradual  and  continued 
as    long    as    the     hypnotic 
sleep    lasted,  that   is,    from 
two    to    five    hours.      The 
curve    during   this    rise   not 
only    reached     the    normal 
waking  level,  but  in  every 
case  it  mounted  above  this 
level,  the  hand  and  fore-arm 
constricting   in   some   cases 
to    an    extent    equal    to    a 
diminution  in  volume  of  as 
much  as  thirty  cubic  centi- 
metres.    In    a    few    experi- 
ments the  rise  in  the  curve 
was    much    sharper,   lasting 
about  one  hour,  the  change 
in   the  volume   of  the   arm 
being    about    the    same    as 
in     those     experiments     in 
which  the  curve  rose  more 
slowly.      When    the    curve 
rose     in     this     more    rapid 
manner,  having  reached  its 
maximal  height  for  the  rapid 
rise,  the  tracing   continued 


1 36  E.  C.  Walden. 

to  rise  much  more  gradually,  with  slight  oscillations,  until  the  end  of 
the  hypnotic  sleep.  At  the  instant  hypnotic  sleep  was  ended  at  the 
suggestion  of  the  experimenter,  there  was  a  sharp  rise  in  the  curve, 
lasting  about  one  minute,  similar  to,  and,  in  many  cases,  as  great  in 
extent  as  the  rise  which  occurred  at  the  beginning  of  the  hypnotic 
suggestion.  In  some  cases  the  diminution  in  the  volume  of  the 
hand  and  fore-arm  during  this  rise  amounted  to  as  much  as  eight 
centimetres.  During  the  rise  the  subject  usually  opened  his  eyes 
and  made  some  movements ;  these  movements,  however,  did  not  per- 
manently affect  the  curve.  After  reaching  its  maximal  level,  the 
curve  began  to  drop,  and  continued  to  fall,  broken  by  sharp  oscilla- 
tions, until  the  tracing  had  reached  about  the  level  it  had  at  the 
beginning  of  the  experiment  previous  to  the  suggestion  of  hypnotic 
sleep.  The  course  of  the  curve  from  this  time  until  the  end  of  the 
experiment  was  in  a  general  horizontal  direction  and  corresponded  in 
every  way  to  the  tracings  of  the  normal  waking  curve.  The  general 
course  of  the  curve  of  hypnotic  sleep  may  then  be  described  as 
follows :  A  sharp  rise,  lasting  from  one  to  ten  minutes,  is  followed 
by  a  slower  fall  very  variable  in  duration,  usually  comparatively 
brief,  but,  in  exceptional  cases,  lasting  for  two  hours.  This  fall  is  in 
turn  followed  by  a  gradual,  long-lasting  rise,  continuing  until  the  end 
of  the  hypnotic  sleep,  after  which  the  curve  sinks  to  the  level  it  had 
previous  to  the  suggestion.  The  general  tendency  of  the  curve 
during  hypnotic  sleep  is  upward,  and  this  change  in  the  record 
corresponds  to  a  constriction  of  the  hand  and  that  portion  of  the 
fore-arm  within  the  plethysmograph. 

Besides  these  general  changes,  other  secondary  variations  were 
observed.  These  have  already  been  alluded  to  in  reference  to  the 
changes  noticed  in  normal  physiological  conditions,  and  probably 
depend  upon  the  activity  of  the  vasomotor  centre.  These  variations 
were  by  no  means  uniform ;  in  some  cases  a  rapid  rise  of  a  few  milli- 
metres was  followed  immediately  by  an  equally  rapid  fall,  while  in 
other  cases,  after  a  fall  or  a  rise,  the  curve  continued  for  several 
minutes  in  a  horizontal  direction  and  then  gradually  returned  to 
about  the  former  level.  These  changes  cannot  be  due  to  external 
stimulation,  since  the  subject  was  quiet,  making  no  movements  what- 
ever, save  those  due  to  respiration.  All  noises  and  other  forms  of 
sensory  stimuli  were  also  excluded  as  carefully  as  possible.  These 
oscillations  are  due,  then,  to  some  internal  stimulus  acting  upon  the 
vasomotor  centre.  In  some  of  the  experiments,  rhythmic,  wave- 


Study  of  Vascular  Conditions  ditring  Hypnotic  Sleep.      137 


like  variations,  such  as 
were  noticed  by  Howell1 
in  normal  sleep,  have  been 
observed ;  these  variations 
were  never  so  pronounced 
in  the  curves  of  hypnotic 
sleep  as  they  are  in  the 
curves  of  normal  sleep, 
and  they  were  not  found 
in  all  of  the  records  of 
hypnotic  sleep,  and  hence 
they  must  be  considered 
as  exceptional,  depending 
upon  the  condition  of  the 
subject  at  the  time  of  the 
experiment. 

Exceptional  curves.  • —  In 
four  of  the  experiments 
of  the  present  series  there 
were  variations  which  have 
not  been  described  in  the 
plethysmographic  curves 
of  other  investigators. 
These  changes,  which  were 
of  two  different  types,  are 
shown  in  Figs.  4  and  5. 
In  one  case,  Fig.  4,  after 
gradually  falling  for  fifty 
minutes,  the  curve  suddenly 
mounted  upward.  In  one 
such  experiment  there  was 
a  diminution  in  the  volume 
of  the  hand  and  that  por- 
tion of  the  fore-arm  within 
the  instrument  of  16.9 
cubic  centimetres  in  three 
minutes,  and  a  further 

1  HOWELL:  Journal  of  ex- 
perimental medicine,  1897,  ii, 
P-  313. 


138 


E.  C.  Walden. 


\ 


\ 


shrinkage  of  5.6  cubic 
centimetres  during  the 
following  fifteen  min- 
utes. This  surprising 
constriction  of  the  arm 
could  not  be  traced  to 
any  external  stimulus, 
nor  to  an  alteration  in 
the  position  of  the  hand 
within  the  plethysmo- 
graph.  No  difference 
could  be  noticed  in  the 
rate  of  the  pulse  or  of 
the  respiration.  After 
this  sudden  rise,  the 
tracing  maintained  the 
high  level  until  the  mo- 
ment of  waking,  when 
after  the  usual  rise  which 
occurs  on  waking,  the 
curve  sank  to  about  the 
level  it  had  at  the  be- 
ginning of  the  experi- 
ment. The  sudden  vari- 
ations already  described, 
due  t'o  vasomotor 
changes,  were  much 
sharper  and  more  nu- 
merous after  this  sudden 
rise  than  they  were  in 
that  portion  of  the  trac- 
ing preceding  it. 

In  Fig.  5,  a  curve  of 
an  opposite  character 
to  the  one  just  described 
is  reproduced.  After  a 
gradual  rise,  lasting 
ninety  minutes,  which 
in  this  case  corresponds 
to  a  diminution  in  the 


Study  of  Vascular  Conditions  during  'Hypnotic  Sleep.      139 

volume  of  the  arm  of  7.6  cubic  centimetres,  the  curve  fell  abruptly, 
the  arm  increasing  in  volume  20  cubic  centimetres  in  seven  minutes. 
After  this  sudden  fall,  the  curve  gradually  rose  for  two  hours  and  five 
minutes,  rising  beyond  the  waking  level.  The  subject  was  then 
awakened.  On  waking,  the  tracing  sank  to  about  the  level  it  had 
previous  to  the  suggestion  of  hypnotic  sleep.  Here,  again,  the  sharp 
variations  of  vasomotor  origin  differed,  those  preceding  the  fall  being 
much  sharper  than  the  oscillations  which  followed  it.  Unfortunately 
the  sudden  fall  occurred  at  a  time  when  the  subject  was  not  under 
close  observation,  and  the  possibility  of  some  external  stimulus  being 
one  of  the  causes  for  the  fall  cannot  be  excluded.  The  position  of 
the  hand  in  the  instrument  could  not  have  been  altered,  for  had  such 
a  change  occurred,  the  tracing  would  not  have  returned  to  so  nearly 
its  former  level  at  the  end  of  the  experiment.  A  point  of  some 
interest  in  this  connection  is  that  these  variations  never  occurred  in 
the  tracing  when  the  subject  was  in  the  best  condition  for  an  experi- 
ment. He  complained  on  each  of  these  occasions  of  not  having  had 
sufficient  sleep  the  night  before,  or  at  the  time  of  the  experiment  he 
was  suffering  with  headache. 

Effect  of  suggestion.  —  A  series  of  experiments  was  undertaken  to 
determine  the  effect  of  various  external  stimuli  upon  subjects  in  dif- 
ferent hypnotic  conditions.  It  was  suggested  to  the  subject  that  his 
arm  had  grown  smaller  or  that  it  had  increased  in  size,  or  he  was 
told  that  he  had  forgotten  his  name  or  could  not  open  his  eyes.  In 
other  cases  it  was  suggested  that  the  subject  would  hear  music  dur- 
ing his  sleep,  and  at  certain  intervals  a  music  box  was  set  into  action. 
The  effect  of  suggestion  during  the  normal  waking  state  was  always 
to  give  a  sharp  rise  in  the  curve  (Fig.  6)  which  lasted  until  the 
suggestion  ended,  when  the  tracing  gradually  sank  to  its  former 
level.  On  suggesting  hypnotic  sleep,  the  phenomena  observed  were 
the  same  as  those  already  described  for  the  hypnotic  sleep  curves. 
During  hypnotic  sleep,  the  curve  having  risen  above  the  normal  wak- 
ing level,  each  suggestion  caused  a  sudden  rise  in  the  tracing  of  from 
one  to  five  millimetres ;  this  rise  was  followed  by  a  sharp  fall  in  the 
curve.  The  fall  was  closely  related  to  the  suggestion  as  it  invariably 
ended  with  the  suggestion,  the  curve  then  gradually  mounted  upward 
until  it  had  reached  about  the  level  it  had  before  the  suggestion  was 
given.  In  suggestion  during  hypnotic  sleep  there  was  always  a  fall 
in  the  curve,  and  in  suggestion  during  the  normal  waking  state  there 
was  always  a  rise  in  the  tracing,  no  matter  what  the  character  of  the 


140 


E.  C.  Walden. 

•I- I I I "I- 


OHIJKLMNOPOR      I         23    45       6.7 


a  9.10 


FIGURE  6. —  Plethysmographic  record  of  the  hand  and  lower  fore-arm,  on  the  right  side, 
taken  December  7,  1899.  This  experiment  was  to  determine  the  effect  of  suggestion 
during  the  normal  waking  and  during  the  hypnotic  sleep.  Mr.  Steele  operator,  and 
C.  D.  H.  subject.  A  fall  of  1  mm.  in  the  original  curve  corresponds  to  an  increase  of 
0-282  c.c.  in  the  volume  of  the  arm.  The  curve  here  presented  has  been  reduced  57 
per  cent.  The  letters  and  figures  show  the  points  at  which  suggestions  were  given, 
and  correspond  to  the  following  :  — 

A.  Suggested  that  the  subject  could  not  open  his  eyes. 

B.  Suggested  that  the  subject  could  open  his  eyes. 

C.  Suggested  that  the  right  arm  of  the  subject  was  swelling. 

D.  Suggested  that  the  arm  had  returned  to  its  normal  condition. 

E.  At  this  point  the  subject  was  left  alone  in  the  room  in  order  to  see  if  the  curve 
would  sink  to  the  level  it  had  originally. 

F.  Came  back  into  the  room. 

G.  Suggested  that  the  subject  could  not  open  his  eyes. 
H.  Suggested  that  the  subject  could  open  his  eyes. 

I.  Suggested  that  the  right  arm  of  the  subject  was  swelling.     The  subject  at  this 
time  made  a  great  many  movements. 

J.  Suggested  that  the  arm  was  normal. 
K.  Suggested  that  his  right  arm  had  diminished  in  size. 
L.  Suggested  that  his  arm  was  normal. 

M.  Suggested  that  there  was  an  increased  flow  of  blood  to  the  arm. 
N.  Suggested  that  the  arm  was  normal. 
O.  Suggested  that  the  arm  was  constricting. 

P.  Suggested  that  the  arm  was  normal. 
Q.  Suggested  that  the  arm  was  dilating. 
R.  Suggested  that  the  arm  was  normal. 

1.  Quiet  hypnotic  sleep  was  suggested. 

2.  Suggested  that  the  arm  was  swelling. 

3.  Suggested  that  the  arm  was  normal,  this  suggestion  was  followed  by  the  sugges- 
tion of  deeper  hypnotic  sleep. 

4.  Suggested  that  the  arm  was  constricting. 

5.  Suggested  that  the  arm  was  normal. 

6.  At  this  time  the  subject  had  a  coughing  fit. 

7.  Suggested  deeper  hypnotic  sleep. 

8.  Suggested  that  the  arm  was  swelling. 

9.  Suggested  that  the  arm  was  normal. 

10.  The  subject  was  awakened.     This  occurred  at  2.45  P.  M. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.     141 

suggestion  given  may  have  been.  When  a  suggestion  was  given  to 
a  subject  in  hypnotic  sleep,  he  became  restless  and  acted  as  he  would 
have  done  if  the  suggestion  had  been  given  to  him  while  he  was 
awake.  The  small  but  sharp  rise  followed  by  the  fall  in  the  curve  was 
very  similar  to  the  rise  and  subsequent  fall  which  always  occurred 
on  waking  a  subject  from  hypnotic  sleep.  The  slight  movements 
made  by  him  cannot  account  for  the  fall  in  the  curve,  since  the  same 
movements  were  noticed  when  the  suggestion  was  given  during  the 
waking  state,  in  which  case  there  was  a  rise  in  the  curve.  This  fall 
can  be  more  easily  explained  by  assuming  that  in  hypnotic  sleep  the 
voice  of  the  operator  partially  awakened  the  subject.  The  small 
rise  which  preceded  the  longer  fall  also  adds  weight  to  this  assump- 
tion. The  rise  which  followed,  the  suggestion  having  ceased,  would 
correspond  to  a  return  of  the  deeper  hypnotic  sleep. 


DESCRIPTION  OF  OTHER  PHENOMENA. 

Blood-pressure  curves.  —  Mosso,1  Frangois-Franck,2  Gley,3  Hill,* 
Colombo,5  and  others  have  demonstrated  by  various  methods  that 
muscular  and  mental  activity,  the  position  of  the  body,  the  time  of 
day,  and  barometric  conditions  may  all  have  an  effect  upon  the  blood- 
pressure.  It  is  known  that  during  normal  sleep  the  blood-pressure 
is  lower  than  it  is  under  similar  conditions  when  the  individual  is 
awake.  As  the  vasomotor  phenomena  accompanying  hypnotic 
sleep  are  the  reverse  of  those  found  in  normal  sleep,  it  was  decided 
to  determine  whether  there  was  as  marked  a  difference  in  the  blood- 
pressure.  It  would  be  but  natural  to  expect  a  rise  in  arterial  pres- 
sure as  an  accompanying  phenomenon  to  the  vaso-constriction  of  the 
cutaneous  blood  vessels,  but  such  is  not  the  case.  In  fact,  it  is 
impossible  to  compare  the  curves  representing  the  volume  changes 
in  the  arm,  taken  by  means  of  the  plethysmograph,  with  the  curves 
registered  by  the  sphygmomanometer.  While  the  plethysmographic 

1  Mosso:  Archives  italiennes  de  biologic,  1895,  xxiii,  p.  177. 

2  FRANCOIS-FRANCK  :  Travaux  du  laboratoire  de  M.  Marey,  1877,  p.  273. 

8  GLEY  :  Expose'  des  donne'es  experimentales  sur  les  correlations  fonctionnelles 
chez  les  animaux,  Paris,  1897;  fitude  expe>imentale  sur  I'e'tat  du  pouls  caroti- 
dien  pendant  le  travail  intellectuel,  Paris,  1881. 

4  HILL  :  Journal  of  physiology,  1895,  xviii,  p.  15  ;  1897-98,  xxii,  p.  xxvi;  1898- 
99,  xxiii,  p.  iv. 

6  COLOMBO  :  Archives  italiennes  de  biologic,  1899,  xxxi,  p.  345. 


142 


E.  C.  Walden. 


curves  are  all  of  them  more  or  less  similar,  the  blood-pressure  curves 
differ  greatly  from  each  other,  and  hence  it  is  difficult  to  determine 
what  the  normal  pressure  curve  is  during  hypnotic  sleep.  The 
characteristic  changes  in  the  blood-pressure  can  only  be  recognized 
by  taking  the  observations  secured  in  a  number  of  experiments,  and 
from  them  constructing  a  mean  curve.  The  pressure  observations 
taken  in  five  experiments  have  been  tabulated  in  the  table  given 
below.  The  observations  were  made  at  intervals  of  fifteen  minutes 
during  the  time  the  experiment  lasted,  and  they  include  the  pressure 

TABLE   I. 


Experiment. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14  15 

16 

17  IS 

Dec.  13. 

60 

50 

50 

55 

60 

58 

56 

54 

50 

48 

50 

50 

54 

56  56 

56 

58  76 

Dec.  15. 

80 

76 

72 

69 

77 

90 

93 

88 

90 

91 

93 

97 

96 

98  95 

88 

87102 

Dec.  21. 

93 

80 

100 

94 

94 

69 

91 

81 

75 

72 

79 

76 

% 

97  96 

101 

102  103 

Jan.  11. 

96 

87 

93 

98 

98 

95 

97 

98 

99 

98 

95 

99 

— 

—  — 

— 

—  105 

Jan.  16. 

70 

72 

77 

77 

71 

66 

68 

70 

72 

66 

68 

70 

72 

66  91 

97 

99  99 

Average.  .  .  80 

73 

78 

78 

80 

76 

81 

78 

77 

71 

84 

84 

86 

S3  82 

82 

82  97 

observations  taken  just  before  the  suggestion  was  given,  and  those 
secured  after  the  suggestion  had  been  finished,  as  well  as  the  obser- 
vations made  during  the  period  of  hypnotic  sleep.  In  the  first 
column  to  the  left  are  given  the  pressure  readings  taken  just  before 
the  suggestion  was  given ;  the  following  sixteen  columns  contain  the 
observations  taken  at  stated  intervals  during  the  suggestion ;  and  the 
last  column  contains  the  readings  taken  just  after  the  subject 
awakened. 

In  order  to  secure  the  general  blood-pressure  curve  from  these 
experiments;  the  average  height  of  the  pressure  at  each  interval  was 
taken,  and  from  these  figures  a  curve  was  plotted.  This  curve  is  given 
below. 

The  average  blood-pressure  in  the  fingers  in  a  horizontal  position 
was  found  to  be  eighty  millimetres  of  mercury.  Mental  and  muscular 
activity,  or  sensory  stimulation  of  any  kind,  increased  the  pressure, 
this  increase  varying  from  five  to  thirty-five  millimetres  of  mercury 
according  to  the  nature  of  the  stimulus.  In  order  to  avoid  as  far  as 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.     143 

possible  all  external  stimuli,  the  subject  was  kept  quiet,  and  the 
observers  made  no  unnecessary  noise  or  movements.  After  one  or 
two  experiments,  the  subject  became  so  accustomed  to  the  apparatus 
that  on  lying  down,  he  soon  began  to  show  signs  of  sleepiness.  The 
pressure  readings  were  begun  when  the  subject  had  reached  this 
condition,  and  the  height  of  the  mercury  was  assumed  to  be  equal  to 
the  arterial  pressure  of  the  individual  without  marked  mental  or 
sensory  stimulation.  Following  the  hypnotic  suggestion,  there  was 
a  fall  in  the  arterial  pressure,  which,  on  the  average,  amounted  to 
seven  millimetres  of  mercury.  After  this  fall,  the  pressure  fluttered 
around  the  normal  level ;  the  tendency  during  the  first  part  of  the 


too 

95 
90 

as 

80 
7S 
70 

? 

3 

4 

5 

6 

7 

8 

9    1 

0     1 

1      1 

?      / 

3    1 

4-     / 

5     / 

6    1 

7      t 

8 

1 

1 

^^^x1 

^^^ 

1 

/ 

/ 

i 

^•s 

"-  --. 

1 

\ 

/ 

^ 

\ 

/ 

^ 

\. 

/ 

\ 

f 

\ 

/ 

FIGURE  7. —  General  curve  of  the  blood-pressure  during  hypnotic  sleep.  The  figures 
along  the  abscissa  represent  consecutive  periods  of  fifteen  minutes.  The  figures 
along  the  ordinate  represent  the  blood-pressure  in  the  fingers  in  millimetres  of 
mercury. 

experiment  was  for  the  pressure  to  remain  below  the  normal  level, 
while  during  the  remainder  of  the  experiment  the  curve  was  above 
the  normal  level.  When  the  suggestion  of  hypnotic  sleep  was  ended, 
the  pressure  rose  rapidly,  the  average  increase  in  the  pressure  being 
seventeen  millimetres  above  the  pressure  at  the  beginning  of  the 
experiment  and  fifteen  millimetres  above  the  pressure  just  before  the 
end  of  the  hypnotic  sleep. 

It  was  never  possible  to  continue  the  pressure  observations  for  any 
length  of  time  after  the  subject  was  awakened.  On  this  account  it 
was  not  determined  how  soon  the  pressure  returned  to  the  normal  level 
after  the  suggestion  was  ended.  That  it  does  not  return  to  this  level 
as  rapidly  as  the  plethysmographic  curve  returns  to  its  base  line  is 


144 


E.  C.  Walden. 


or 


evident,  since  the  experiment  was  never  stopped  until  the  plethysmo- 
graphic  curve  had  reached  about  the  level  it  had  at  the  beginning  of 
the  experiment,  and  in  every  case  the  pressure  curve  was  still  much 
above  this  level.  The  marked  rise  at  the  end  of  the  curve  was  coin- 
cident with  slight  muscular  movements  made  by  the  subject  at  this 
time,  and  an  increased  heart  rate  which,  as  will  be  shown,  was  also 
very  striking. 

In  hypnosis,  therefore,  the  general  course  of  the  blood-pressure 
curve  is  in  a  horizontal  direction,  the  pressure  varying  but  little  from 
the  level  it  had  previous  to  the  suggestion.  On  waking  there  is  a 
sudden  rise  in  the  curve,  which  is  in  all  probability  due  to  the  effect 
of  increased  mental  and  muscular  activity  on  the  heart  rate,  as  de- 
scribed in  the  next  section. 

The  pulse  rate.  —  The  general  pulse  rate  curve  was  determined  by 
the  same  method  that  was  used  to  obtain  the  general  blood-pressure 
curve  during  hypnotic  sleep.  The  pulse  rate  curves  in  the  different 
experiments  did  not  show  the  great  differences  among  themselves 
that  were  noticed  in  the  blood-pressure  curves.  The  general  char- 
acter of  these  curves  was  the  same  in  all  of  the  experiments,  and 
only  in  the  minor  variations  were  there  any  differences.  The  table 
given  below  contains  the  observations  taken  in  the  same  experiments 
from  which  the  observations  of  the  blood-pressure  were  obtained. 

TABLE   II. 


Experiment. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

Dec.  12. 

58 

56 

57 

52 

58 

62 

58 

57 

54 

54 

54 

56 

56 

57 

57 

58 

62 

74 

Dec.  15. 

64 

62 

62 

62 

60 

62 

60 

61 

64 

66 

65 

60 

64 

60 

54 

56 

61 

68 

Dec.  21. 

62 

58 

55 

60 

64 

63 

64 

62 

58 

60 

58 

66 

67 

57 

69 

72 

60 

70 

Jan.  11. 

68 

60 

60 

63 

57 

56 

52 

58 

60 

60 

60 

62 

60 

— 

— 

— 

— 

64 

Jan.  16. 

56 

52 

60 

52 

52 

56 

52 

52 

60 

60 

60 

58 

60 

— 

— 

— 

— 

62 

Average  .  .  62 

58 

59 

58 

58 

60 

57 

58 

59 

60 

59 

60 

61 

58 

60 

62 

61 

67 

From  the  table  it  will  be  seen  that  before  hypnotic  sleep  was  sug- 
gested, the  pulse  rate  was  sixty-two  per  minute ;  after  suggestion  there 
was  a  fall  in  the  rate  to  fifty-eight  per  minute.  During  the  entire 
period  of  hypnotic  sleep,  the  rate  varied  about  this  figure,  the  aver- 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      145 

age  rate  for  the  entire  period  of  hypnotic  sleep  being  fifty-nine  pulsa- 
tions per  minute.  The  tendency  of  the  pulse  curve  was  to  rise 
gradually,  the  heart  beating  less  frequently  at  the  onset  of  hypnotic 
sleep,  than  it  did  after  the  subject  had  been  asleep  for  several  hours. 
After  hypnotic  sleep  had  lasted  for  about  three  hours,  the  pulse  rate 
was  nearly  as  high  as  it  was  just  before  the  suggestion  was  given. 
On  waking  the  subject,  the  pulse  increased  in  frequency,  the  average 
rate  for  the  observation  just  after  the  hypnotic  sleep  had  ended  being 
sixty-seven  pulsations  per  minute.  In  the  accompanying  figure  is 
given  the  plotted  curve  constructed  from  the  averages  given  in  the 
preceding  table. 


9    I 


O     /i 


13 


/6 


67 

66 
65 


62 
<5/ 
€0 
69 
68 
67 


FIGURE  8.  —  General  curve  of  the  pulse  rate  during  hypnotic  sleep.  The  figures  along 
the  abscissa  represent  consecutive  periods  of  fifteen  minutes,  those  along  the 
ordinate  represent  the  number  of  heart-beats  per  minute. 

The  table  and  figure  both  show  that  the  heart  rate  was  slower  dur- 
ing hypnotic  sleep  than  during  the  waking  state,  they  also  show  that 
this  effect  upon  the  heart  rate  was  greater  at  the  beginning  of  the 
hypnosis  than  it  was  after  the  hypnotic  sleep  had  continued  for  a 
considerable  time,  since  the  rate  gradually  increased  until  at  the 
end  of  four  hours  the  heart  had  about  the  same  rapidity  as  at  the 
beginning  of  the  experiment.  On  waking,  the  pulsations  were  more 
frequent  than  either  during  or  before  the  hypnotic  sleep.  After 
waking,  the  rate  of  the  pulsations  did  not  return  rapidly  to  the 


10 


146 


E.  C.  Walden. 


rate  previous  to  the  suggestion,  as  it  was  always  faster  when  the  last 
observations  were  made,  about  fifteen  minutes  after  the  subject  had 
been  awakened,  than  it  was  at  the  beginning  of  the  experiment. 

Respiration.  —  It  is  well  known  that  during  periods  of  mental  and 
muscular  rest,  as  well  as  in  sleep,  the  respiration  is  slower  than  dur- 
ing periods  of  activity.  Since  in  hypnotic  sleep,  there  are  but  few 
movements,  it  is  but  natural  to  expect  that  the  respirations  would  be 
less  frequent,  and  such  is  the  case.  Hoover  and  Sallman  *  have 
observed  the  changes  in  the  respiration  in  a  hypnotic  subject  who 
was  in  a  hypnotic  state  for  one  week.  During  this  period,  the  res- 
piration was  slower  than  normal,  except  at  those  times  when  the 
subject  made  muscular  movements.  At  such  times  there  was  an 
increase  in  the  frequency  of  the  respirations  which  these  authors 
attribute  entirely  to  the  movements.  In  the  present  experiments, 
the  hypnotic  state  was  much  shorter  than  in  the  experiment  referred 
to,  and  but  few  movements  were  noticed.  In  the  table  given  below 
are  tabulated  the  observations  of  the  respiratory  rate  and  the  average 
rate  at  each  reading  taken  in  the  five  experiments  from  which  the 
pulse  and  pressure  observations,  already  described,  were  obtained. 

TABLE   III. 


Experiment. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

Dec.  12. 

16 

18 

18 

16 

16 

16 

17 

16 

16 

16 

16 

18 

17 

17 

17 

16 

17 

22 

Dec.  15. 

19 

16 

19 

16 

16 

16 

16 

18 

20 

16 

12 

15 

16 

16 

20 

16 

16 

20 

Dec.  21. 

22 

16 

16 

16 

16 

17 

16 

16 

16 

17 

15 

16 

16 

17 

12 

18 

16 

20 

Jan.  11. 

18 

18 

18 

21 

18 

IS 

20 

16 

17 

16 

16 

17 

20 

— 

— 

— 

— 

20 

Jan.  16. 

16 

15 

16 

16 

15 

15 

14 

15 

16 

18 

18 

19 

16 

— 

— 

— 

— 

18 

Average  .  .  18 

17 

17 

17 

16 

16 

17 

16 

17 

17 

15 

17 

17 

17 

16 

17 

16 

20 

It  will  be  noticed  that  while  in  some  of  the  experiments  the 
variations  were  well  marked,  in  others  there  was  but  little  difference 
in  the  respiratory  rate  during  the  whole  experiment.  This  can  only 
be  accounted  for  by  assuming  that  the  subject  was  less  restless  in 
those  experiments  in  which  the  variations  were  but  little  marked 
than  in  those  cases  where  the  differences  between  the  wakine  and  the 


HOOVER  and  SALLMAN  :  Journal  of  experimental  medicine,  il 


or  THE 


UNIVERSITY 

or 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.     147 


hypnotic  conditions  were  more  prominent.  The  average  figures  for 
the  experiments  show  that  there  was  a  fall  in  the  respiratory  rate 
during  the  period  of  hypnotic  sleep.  In  the  accompanying  figure  is 
shown  the  general  course  of  the  curve  of  the  respiratory  rate  during 
hypnotic  sleep. 


5      6 


8      9    /O    / 


tf> 


J£- 


\ 


FIGURE  9.  —  General  curve  of  the  respiratory  rate  during  hypnotic  sleep.  The  figures 
along  the  abscissa  represent  consecutive  periods  of  fifteen  minutes,  those  along  the 
ordinate  represent  the  number  of  respirations  per  minute. 

At  the  moment  of  hypnotic  suggestion  there  was  a  fall  in  the 
curve ;  during  the  entire  period  of  hypnotic  sleep  it  ran  a  horizontal 
course  with  slight  variations,  and  on  waking  it  rapidly  mounted 
upward,  passing  the  level  it  had  at  the  beginning  of  the  experiment. 

Temperature.  —  It  has  only  been  possible  to  obtain  observations 
of  the  rectal  temperature  in  two  experiments.  The  course  of  the 
curves  constructed  from  these  observations  was  the  same  in  the 
two  experiments,  and  the  general  curve  constructed  from  the  obser- 
vations may  be  safely  assumed  to  represent  the  general  course  of 
the  rectal  temperature  during  hypnotic  sleep.  Table  IV.  contains 
the  temperature  observations  taken  in  the  two  experiments  and  also 
the  averages  obtained  from  these  observations,  and  Fig.  10  repre- 
sents the  curve  plotted  from  the  mean  figures. 

These  observations  and  the  plotted  curve  of  the  general  course 
of  the  curve  of  the  rectal  temperature  show  that  there  is  but  little 
change  in  the  rectal  temperature. 

The  rectal  temperature  was  always  higher  at  the  beginning  of  the 
experiment  than  it  was  at  any  time  during  the  rest  of  the  experiment. 
On  suggesting  hypnotic  sleep,  there  was  a  slight  fall  in  the  tem- 
perature, and  during  the  period  of  hypnotic  sleep  the  temperature 
slowly  and  gradually  fell.  When  the  subject  was  awakened  the 
temperature  rose,  but  it  did  not  reach  the  height  it  had  before  the 
suggestion  was  given. 


148 


£.  C.  Walden. 


Average 

P 

'-n 

1 

O 

I 

Experiment. 

2  3  B  ~ 

g 

\c  o 

N) 

s 

b 

bo 

- 

b 

CO 

5^ 

CO   | 

b 

C^J    C^i 

Vl 

b  ;   H-  •  \c 

» 

SO 

b  vc 

- 

O 

^J   CN      co 

i-^   vC 

bo 

'^   ^   ^   vC 

s 

Osi 

b 

£   5 

g 

b 

£ 

bo 

»—  ' 

bo 

£  £ 

\C   CO 

to 

^\     ^ 

bo  |   b 

$ 

Co 

1 

b 

£ 

5 

^r   j   Sa   ^J 

I—I 
'-n 

s 

bo 

bo 

s 

bo 

bo 

bo 

" 

1 

1  1 

CO 

It  may  be  said  that  the  general  effect 
of  hypnotic  sleep  is  to  slightly  lower  the 
rectal  temperature. 

Surface  Temperature.  —  The  effect  of 
hypnotic  sleep  upon  the  temperature  of 
the  skin  was  different  from  the  effect  upon 
the  rectal  temperature.  The  variations  in 
the  temperature  were  not  the  same  in  the 
two  arms,  the  changes  being  less  marked 
in  the  arm  surrounded  by  the  water  in  the 
plethysmograph  than  in  the  other  arm. 
Table  V.  contains  the  temperature  obser- 
vations taken  in  five  experiments  and  Fig. 
1 1  the  curves  plotted  from  the  average 
observations  of  the  two  arms. 

The  general  course  of  the  temperature 
curves  in  the  two  arms  was  the  same.  The 
general  course  of  the  curve,  as  shown  in 
the  figure,  was  as  follows :  On  suggest- 
ing hypnotic  sleep,  the  temperature  rose 
rapidly,  as  determined  by  observations  at 
intervals  of  fifteen  minutes,  this  rise  con- 
tinuing for  about  one  hour,  after  which 
the  curve  slowly  and  steadily  sank  until  the 
end  of  hypnotic  sleep ;  on  awakening  the 
subject,  the  curve  rose  rapidly,  reaching 
a  higher  level  than  it  had  at  any  previous 
time  during  the  experiment. 

It  will  be  seen  that  the  general  course 
of  the  temperature  curves  of  the  skin  and 
rectum  is  not  the  same.  While  the  rectal 
temperature  remains  nearly  uniform,  sink- 
ing slowly  though  slightly  during  hyp- 
nosis, and  showing  but  little  rise  on 
waking,  the  skin  temperature  follows  in 
general  a  reverse  course  to  that  of  the 
plethysmographic  record,  rising  during  the 
first  part  of  hypnosis,  sinking  during  the 
latter  portion  of  the  sleep,  and  rising 
suddenly  and  markedly  upon  awakening. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      149 

It  should  be  noted,  however,  that  the  general  temperature  of  the  skin 
during  the  hypnosis  was  above  that  observed  at  the  time  the  sugges- 
tion was  given. 

DISCUSSION  OF  RESULTS. 

Suggested  explanation  of  the  meaning  of  the  plethysmographic 
curves.  —  The  changes  which  occur  in  the  arm  as  the  result  of 
mental  and  muscular  rest  and  activity  have  been  shown  to  be  due, 
in  all  probability,  to  vasomotor  dilatation  and  constriction  of  the 
cutaneous  blood  vessels.  Mosso  1  has  clearly  shown,  in  individuals 
with  defective  skulls,  that  there  is  a  diminution  in  the  volume  of 


37.1 
37. 

36.9 
368 
367 

/ 

2 

3 

4- 

S 

6 

7 

8 

9    / 

0    / 

1      / 

2    / 

3    / 

#    / 

5    / 

6    t 

?     / 

e 

\ 

\ 

z 

\ 

\ 

/ 

\ 

/ 

\ 

/ 

FIGURE  10.  —  Plotted  curve  of  the  rectal  temperature  observations  in  hypnotic  sleep. 
Average  before,  37.1°;  during,  36.9°  ;  after  hypnotic  sleep,  36.9°.  The  figures  along 
the  abscissa  represent  consecutive  periods  of  fifteen  minutes,  those  along  the 
ordinate,  the  temperature  in  tenths  of  a  degree  centigrade. 

the  brain  during  normal  sleep,  and  he  attributes  this  shrinkage  in  the 
volume  of  the  brain  to  a  diminished  amount  of  blood  in  the  blood 
vessels  of  the  brain.  TarchanofF2  has  shown  that  in  sleeping  dogs 
there  is  a  fall  in  the  blood-pressure,  and  that  on  waking  the  pressure 
again  mounts  upward.  Since  the  vasomotor  changes  in  the  cuta- 
neous vessels  are  not  local,  but  general,  this  fall  in  the  blood-pressure 
is  easily  accounted  for  by  the  diminution  in  peripheral  resistance, 
by  the  diminished  heart  rate  and  respiratory  rate.  Howell 3  has 
observed  that  there  is  a  marked  increase  in  the  size  of  the  arm  and 

1  Mosso:    Ueber  den  Kreislauf  des  Blutes  im  menschlichen  Gehirn,  Berlin, 
1881;  Die  Temperatur  des  Gehirns,  Berlin,  1894. 

2  TARCHANOFF  :  Archives  italiennes  de  biologic,  1894,  xxi,  p.  318. 
8  HOWELL:  Journal  of  experimental  medicine,  1897,  ii,  p.  313. 


E.  C.  Walden. 


\ 

•sr  c  s  s  2 

c   o>   a   n   o 
r^   o   o   o   < 

p  r  £  $  is 

> 

" 

3 

QJ       \^'      ^^      ^^      ^ 

?  s  B  P  5 
P  S2  K  5  is 

W 

X 

1 
s' 

OQ 
? 

§   eg   eg   eg   oo 
.  g  S  vs  ^8 

P 

§    GO    CO    CC    CO 
P   vS   S   v*   g 

a> 
3 

s 

--? 

OO   OJ   OJ   OJ   do 

OJ    C^J    C^J    C^J    O 

to   b   :-n   *<r   U> 

OJ 
CO 
ON 

OJ    OJ    UJ    OJ    Co 
Co    CO    to    CO    t/J 
b   '^n   CO   CO   Co 

- 

Co 

co 
b 

C^J    OJ    C^J    OJ    OJ 
4^    U)    C^>    OJ    O 
b    4^    I"    C>    '^n 

OJ 
CO 

o 

Co   Co   Co   Co   U) 
CO    CO    C/J    CO    OJ 
C\    'In    '^i    4^    Co 

to 

Co 

5*» 

0 

C^O    CA>    C^    C^J    C^J 

CM   CM   w«i   OJ   p 

CO    In   ^    Cn    <> 

u> 

CO 

vO 

Co   Co   Co   Co   Co 
CO    CO    C^J    CO    O-> 
•<!    CN    *<I    CO    OJ 

OJ 

& 

b 

OJ   C^o   Oo   J^o   Oo 
U)    C^J    Os)    U>    O 
CO   'Ln   CC   4*   CN 

W 

f—  ' 

Co   Co   Co   Co   Oo 
Co   CO   4^   CO   Co 

b  -<i  b  co  co 

^^ 

£ 

u> 

Oo   OJ   C^J   Oo   Oo 

U>   OJ   -u   4-   O 

^  co   b   i^j   •>• 

CM 

Oo 

CM   CM   CM   CM   CM 

Co   Co   4^   CO   Co 

b  b  b  ^—  co 

^-n 

£3 

to 

Co   CM   CM   O4   OJ 
CM   CM   CM   4*-   O 

^   00    CO    U>    4^ 

S3 

f—  i 

CM   CM   CM   CM   CM 
CM   CM   CM   to   CM 

CO    O    CO    t-'    Co 

ON 

£ 

CO 

U>   -fi-   CM   4*   O 

^<r   b   co   to   U) 

M 

CD 

C^J 

Co 

b 

OJ    CO    C^J    CM    ^J 
Co   Co   Co   CO   Co 

b   co  ^j  b  co 

^r 

X 

en' 

IS 

to 

^   %   ^   4^   0 
In    U*   \O    4*    O 

> 
>1 

3 

is 

vO 

Co   Co   Co   Co   Co 
to   CM   4^.   co   co 

•vi   Co   b   i—'   in 

00 

> 

Co 

OJ 

CM   CM   CM   CM   CM 

U)    -^    >^>    4»>    C 

u>  oj  ^i  u>  b 

g 

Co   Co   Co   Co   Co 
CO   Co   4>-   CO   CO 

in   4..    O    H-1    CO 

vO 

g 

b 

C^J    UJ    Oo    t*J    tO 
U)    4^    OJ    4-    \O 

b  '>-"  ^»  c^j  co 

OJ 
CO 

^ 

Co   Co   Co   Co   Co 
CO   Co   Co   CO   CO 
jv    O    *-4    CO    CO 

0 

co 
to 
vO 

Os>    OJ    OO    C^J    to 
OJ   4^-   OJ   4»-   vC 
to   In   4^   LM   b 

is 

•<r 

OJ    C^J    CO    C/J    OJ 
CO    CO    CO    CO    CO 
«<t   C>   <-n   CO   CO 

- 

CO 
CO 

OJ    U>    U>    OJ    tO 
C^>    44.    CA>    4*    GO 

C/J 

^ 

Co   Co   Co   Co   Co 
CO    Co    Co    CO    CO 

CO 

w         wJ    CO 

Co 

to 

•vj 

OJ    C/J    Oo    tO 
-^    U)    -^    CO 
I     CO   CO   CM   In 

OJ 
CO 

vO 

Co   Co   Co   Co 
Co    Co    CO    CO 
I     vO   '-n   d/J   CO 

Co 

Oo 
to 
•<J 

Oo    OJ    CA>    CO 

-^    U)    -^    CO 
I     CO   b   4^   CN 

CM 

CO 
\C 

Co   Co   Co   Co 
4^   OJ   CO   CO 

I   b  u>  4^   co 

(—  i 
4^ 

CM 

t* 

-I 

Co   oj   u>   ro 

4-   to   4^   CO 
I    Co   -<r   4^   ^ 

U) 

to 

vO 

Oo    O->    CO    Oo 
4^    Co    CO    CO 
I     O    CO    4*-    H-1 

i—  i 
t^i 

CO 

to 

CN 

OO    U»    OJ    CO 
4^   CO   4^   CO 
'     vO   In   CM   ^ 

U> 

S 

OJ    Co    C/J    OJ 

-^   co   co   co 
1   b  b  co  co 

C> 

&s 

Cn 

OJ   Oo   Oo   CO 
;    yi   co   yo   po 

O    '-n    CO    CO 

JS 

\o 

Co   Co   Co   Co 
•     -fi-    CO    CO    CO 

!    co   b   H-"   co 

i—  " 
•<! 

£ 

to   CM   oj   oj   co 

—   v\   ^-<   —   \C 

b  co  b  Ot  o 

& 

'•<* 

Co   Co   Co   Co   Co 
OJ    *vi    OJ    4^    CO 
<-n   b   Cv   CO   Co 

00 

Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      151 


hand  during  normal  sleep  due  probably  to  a  vascular  dilatation  of 
the  skin.  This  dilatation  follows  a  definite  course  and  passes  off 
gradually  toward  the  time  of  spontaneous  waking. 


/6     l\7 


337 

33.6 

33.6 

334 

333 

33.2 

331 

33. 

32.3 

32B 

327 

32.6 


\ 


IL 


324 
323 


FIGURE  11.  —  Plotted  curves  of  the  general  course  of  the  skin  temperature  in  the  two 
arms  during  hypnotic  sleep.  The  unbroken  line  represents  the  right  arm,  the  broken 
line  the  left  arm.  The  figures  on  the  abscissa  represent  consecutive  periods  of  fifteen 
minutes,  those  on  the  ordinate,  the  temperature  in  tenths  of  a  degree  centigrade. 

In  psychical  activity,  phenomena  of  an  exactly  opposite  nature 
have  been  observed  by  many  investigators,  among  whom  are 
Mosso,1  Kiesow,2  Shields,3  and  Binet  and  Courtier.4  These  authors 

1  Mosso:    Ueber  den  Kreislauf  des  Blutes  im  menschlichen  Gehirn,  Berlin, 
1881 ;  Die  Temperatur  des  Gehirns,  Berlin,  1894;  Archives  italiennes  de  biologic, 
1895,  xxiii,  p.  177. 

2  KIESOW  :  Archives  italiennes  de  biologic,  1895,  xxiii,  p.  198. 

3  SHIELDS:  Journal  of  experimental  medicine,  1896,  i,  p.  74. 

4  BINET  and  COURTIER:  L'annde  psychologique,  1897,  iii,  p.  10. 


X  '^''  • 

{  UNIV 
152  -ZT.  C  Walden. 

claim  that  there  is  a  peripheral  vaso-constriction  and  a  rise  of  blood- 
pressure  with  increased  psychic  activity.  Gley,1  MacDougal,2  and 
Mentz  3  have  observed  a  more  rapid  pulse  rate  under  the  same  con- 
ditions. Binet  and  Courtier4  have  shown  that  the  rise  in  blood- 
pressure  differs  in  various  conditions  of  mental  activity,  the  pressure 
often  being  augmented  as  much  as  thirty  millimetres  of  mercury. 
The  rise  in  the  blood-pressure  in  the  case  of  mental  activity  is  due, 
in  part,  to  an  increase  in  the  tone  of  that  portion  of  the  vasomotor 
centre  controlling  the  peripheral  vessels,  and  in  part  to  an  increase  in 
the  pulse  rate.  It  is  evident  from  the  results  obtained  by  these 
authors  that  mental  activity  causes  a  constriction  of  the  peripheral 
blood  vessels  and  a  rise  of  blood-pressure,  and  therefore  presumably 
a  greater  flow  of  blood  to  the  brain,  while  sleep  is  accompanied  by  a 
dilatation  of  the  peripheral  vessels  and  probably  a  diminished  flow  of 
blood  to  the  brain. 

Salvioli 5  claimed  that  a  constriction  of  the  peripheral  vessels  and 
a  consequent  augmentation  of  the  blood  in  the  brain  is  the  character- 
istic phenomenon  of  hypnotic  sleep. 

Tamburini  and  Seppilli,6  from  plethysmographic  experiments 
made  by  them,  distinguish  between  two  conditions  in  hypnotic  sleep, 
namely,  the  lethargic  and  the  cataleptic  states.  During  the  lethargic 
condition  they  observed  that  the  arm  dilated,  while,  on  the  contrary, 
in  the  cataleptic  state  there  was  a  diminution  in  the  volume  of  the 
arm,  which  they  attribute  to  a  constriction  of  the  vessels.  They 
further  observed  that  the  pulse  was  more  frequent  during  hypnotic 
sleep  than  it  was  under  normal  conditions,  but  that  there  was  no 
noticeable  difference  in  this  respect  in  the  two  hypnotic  states.  The 
constriction  of  the  peripheral  vessels  at  the  moment  the  subject 
passes  from  the  lethargic  into  the  cataleptic  state,  these  authors  ex- 
plain as  the  result  of  a  vascular  reflex  produced  by  the  hypnotic 
stimulant,  either  mechanical,  acoustic,  or  visual ;  this  reflex  being 

1  GLEY:  Expose'  des  donnees  experimentales  sur  les  correlations  fonctionnelles 
chez  les  animaux,  Paris,  1897:  Etude  experimental  sur  l^tat  du  pouls  carotidien 
pendant  le  travail  intellectuel,  Paris.  1881. 

2  MACDOUGAL:  Psychological  review,  March,  1896,  p.  158. 

3  MENTZ  :  Die  Wirkung  akustiker  Sinnesreize  auf  Puls  und  Athmung,  Philo- 
sophische  Studien,  1895,  xi,  p.  61. 

4  BINET  and  COURTIER:  L'annee  psychologique,  1897,  iii,  p.  10. 

5  SALVIOLI:  Archivio  di  psichiatria  e  scienze  penali,  1881,  quoted  from  Tam- 
burini and  Seppilli. 

6  TAMBURINI  and  SEPPILLI:  Archives  italiennes  de  biologic,  1882,  ii,  p.  273. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      153 

analogous  to  that  produced  in  normal  sleep  by  external  stimuli, 
which  cause  an  afflux  of  blood  to  the  brain.  In  these  experiments 
the  authors,  so  far  as  can  be  determined  from  their  records,  published 
in  the  Archives  italiennes  de  biologic,  made  observations  only  upon 
the  immediate  effects  of  hypnotic  sleep.  Their  experiments  seem  to 
have  continued  only  a  few  minutes.  In  part,  these  observations 
agree  with  the  experiments  described  in  the  present  paper.  The 
division  of  hypnotic  sleep  into  two  states,  the  lethargic  and  the  cata- 
leptic, does  not  seem  necessary.  In  fact,  in  all  of  the  experiments 
performed  in  this  series,  the  plethysmographic  tracings  took  a  gen- 
eral course,  which  corresponds  to  the  curves  obtained  in  the  catalep- 
tic state  by  Tamburini  and  Seppilli.  A  fall  in  the  curve,  such  as 
described  by  them  for  the  lethargic  state,  was  never  observed  in  the 
present  series,  unless  the  gradual  fall  in  the  plethysmographic  curve 
noticed  during  the  first  part  of  hypnotic  sleep  be  considered  as  such. 
Their  observations  on  the  frequency  of  the  pulse  are  the  reverse  of 
those  obtained  in  the  present  series  of  experiments.  The  observa- 
tions of  these  authors  were  taken  during  a  very  few  minutes  at  most, 
and  embraced  that  period  during  which  the  suggestion  was  being 
given,  while  the  observations  in  the  present  investigation  cover  a 
period  of  several  hours.  As  is  well  known,  both  mental  and  muscu- 
lar activity  exert  an  influence  upon  the  rate  of  the  heart-beat,  the 
pulse  increasing  in  frequency  with  greater  mental  or  muscular  activ- 
ity. This  effect  is  well  shown  by  the  more  rapid  pulse  on  waking  a 
subject  from  hypnotic  sleep,  and  is  also  apparent  on  waking  from 
normal  sleep.  On  account  of  the  increased  mental  activity  connected 
with  the  act  of  suggestion,  it  is  but  natural  to  expect  an  increase  in 
the  heart  rate  during  this  period.  In  the  present  series  of  experi- 
ments several  minutes  elapsed  between  the  time  the  suggestion  was 
given  and  the  time  at  which  the  first  observation  of  the  heart  rate 
was  made,  and  the  effects  of  the  increased  excitement  had  probably 
disappeared.  The  effect  of  hypnotic  sleep  upon  the  pulse  rate  be- 
comes less  marked  as  the  experiment  progresses,  and,  as  has  already 
been  shown,  after  the  sleep  has  lasted  for  several  hours  the  rate  may 
be  as  high  as  under  normal  conditions. 

What  do  the  plethysmographic  curves  in  the  present  series  of  ex- 
periments upon  hypnotic  sleep  indicate  as  to  the  conditions  of  the 
circulatory  system?  As  has  already  been  shown,  the  curve  is  some- 
what complex.  It  may  be  divided  into  five  distinct  portions:  I.  A 
sudden  short  rise  at  the  time  hypnotic  suggestion  is  being  given, 


154  £-  C-  Walden. 

2.  A  slower,  more  gradual  fall  in  the  curve,  following  immediately 
the  end  of  the  suggestion.  3.  A  gradual,  prolonged  rise,  lasting 
until  the  end  of  the  hypnotic  sleep.  4.  A  sudden  rise  as  the  subject 
is  wakened.  5.  A  gradual  fall  in  the  curve,  after  awakening,  to 
about  the  level  it  had  at  the  beginning  of  the  experiment  In  order 
to  understand  the  causes  to  which  these  variations  are  due,  each 
portion  of  the  curve  will  be  discussed  in  turn. 

1.  The  sudden  rise  at  the  beginning  of  the  hypnotic  sleep  is  simi- 
lar in  every  particular  to  the  rise  observed  under  normal  conditions 
from  increased   psychical   activity.     In  the  case  of  suggestion  it  is 
due,  in  all  probability,  to  the  voice  of  the   operator  acting  as  a  sen- 
sory stimulus,  and  to  the  effort  on  the  part  of  the  subject  to  concen- 
trate his  mind  upon  the  suggestion  given.     The  mental   stimulation 
gives  its  normal   reaction,  causing  a  vaso-constriction  of  the  peri- 
pheral blood  vessels,  and  probably  a  greater  flow  of  blood  to  the 
brain. 

2.  The  fall   that   follows    this    rise    may  be  due   in   part   to   the 
absence  of  external  stimuli,  and   in  all  probability  to  a  diminished 
psychic  activity. 

3.  The  gradual  prolonged  rise  in  the  curve  which  follows  this  fall 
is  the  striking  feature  of  the  plethysmographic  record.     From  the 
observations  of  the  pulse  rate  it  has  been  shown  that  during  hyp- 
notic sleep  there  is  a  slower  rate  than  during  the  waking  condition. 
It  has  also  been   shown  that  the   average   blood-pressure  is  lower 
during  the  period  of  hypnotic  sleep  than  in  those  portions  of  the 
experiment  before  and  after  the  period  of  sleep.     The  gradual  rise 
in  the  curve  is  therefore  to  be  explained  by  a  vaso-constriction  in 
the  parts  observed.     We  may  assume  that  this   constriction  affects 
chiefly  the  skin  vessels,  since  it  is  known  that  they  are  well  sup- 
plied with    constrictor  fibres,   and,  furthermore,  that   this  constric- 
tion   is    not   limited   to   the   parts    examined,    but   affects   the    skin 
generally,  just  as  the  opposite  condition  of  dilatation  does  in  normal 
sleep.     As  to  the  effect  of  this  constriction  on  the  supply  of  blood 
to  the  brain,  we  can  only  suppose  that,  following  the  analogy  of  the 
constriction  observed  in  psychical  activity,  it  would  result  in  a  steady 
increase  in  the  blood  flow  to  the  brain  as  the  constriction  gradually 
progressed.     It  must  be  remembered,  however,  that  unlike  the  con- 
dition of  psychical  activity,  the  pulse  rate  during  this  period  is  below 
normal,  a  factor  which  would  tend  to  have  an  opposite  effect  on  the 
circulation  through  the  brain.     The   general  blood-pressure,  which 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      155 

might  be  considered  as  representing  the  balance  of  these  two 
opposing  factors,  and  therefore  as  determining  whether  or  not  there 
was  probably  an  actual  increase  in  the  blood-flow  to  the  brain,  pre- 
sents an  irregular  course.  Its  characteristics  are  not  sufficiently 
definite  to  admit  of  a  positive  conclusion  in  this  respect,  so  that 
whether  or  not  the  peripheral  constriction  really  results  in  an  in- 
creased flow  to  the  brain  must  remain  undetermined.  It  may  be 
emphasized  here  that  while  during  increased  psychical  activity  we 
have  increased  peripheral  constriction  and  increased  heart  rate, 
during  hypnotic  sleep  these  two  factors  are  dissociated,  the  periph- 
eral constriction  being  increased  and  tending  to  show  a  heightened 
mental  state,  while  the  pulse  rate,  on  the  contrary,  is  lowered  much 
as  it  is  in  normal  sleep. 

4.  The  sudden   rise   in  the   curve  at  the   moment  the  subject  is 
wakened  is  probably  due  to  the  action  of  sensory  and  mental  stimuli 
connected  with  the  act  of  awakening. 

5.  The  large  fall  to  the  normal  which  occurs   when  the  subject 
fully  awakes    is    probably  due    to    the    cessation    of  the    effects    of 
hypnotic  suggestion  and  a  consequent  passing  off  of  the  peripheral 
constriction,  that  is,  to   a  lessening  of  the  tone   of  the  vasomotor 
centre,  aided  possibly  by  a  more  rapid  heart  rate. 

Probable  explanation  of  the  changes  in  the  blood-pressure. — The 
blood-pressure,  as  has  already  been  stated,  does  not  pursue  a  regular 
course  during  hypnotic  sleep,  nor  do  the  curves  obtained  from  the 
different  experiments  have  many  characteristics  in  common. 

Hill1  has  demonstrated  that  in  bodily  rest,  quiet  mental  work  and 
sleep,  there  is  a  fall  in  the  arterial  pressure.  This  has  been  con- 
firmed by  Oliver,2  Colombo,3  and  Johansson.4  On  the  other  hand, 
these  investigators  have  observed  the  effect  of  muscular  activity 
upon  the  blood-pressure,  and  they  state  that  during  muscular  exercise 
there  is  always  an  elevation  of  the  blood-pressure.  With  continued 
exercise  and  in  muscular  fatigue,  the  pressure  does  not  remain  at 
this  high  level,  but  sinks  to  the  normal  and  often  below  the  normal 
level. 

The  same   general  phenomena   have  been   observed  in  psychical 

1  HILL:  The  cerebral  circulation,  London,  1896. 

2  OLIVER:    Journal   of  physiology,    1895,  xviii,  p.  230;    1897-98,  xxii,  p.  li ; 
1898-99,  xxiii,  p.  v. 

3  COLOMBO:  Archives  italiennes  de  biologic,  1899,  xxxi,  p.  345. 

4  JOHANSSON:  Skandinavisches  Archiv  fiir  Physiologic,  1895,  v,  p.  20. 


156  E.G.  Walden. 

activity.  Strong  sensory  excitation  elevates  the  pressure  about  ten 
millimetres  of  mercury,  and  intense  intellectual  work  augments  the 
pressure  more  than  twenty  millimetres,  according  to  the  experiments 
of  Binet  and  Vaschide.1  From  the  experiments  mentioned  it  is 
evident  that  mental  and  muscular  activity  increase,  while  rest  and 
sleep  tend  to  lower  the  blood-pressure. 

Hill,2  in  his  experiments  as  to  the  effect  of  gravity  upon  the 
blood-pressure,  has  discussed  the  interaction  of  the  two  chief  factors 
in  the  regulation  of  the  pressure,  namely,  the  pulse  rate  and  the 
tone  of  the  blood  vessels.  According  to  him,  the  blood-pressure  in 
the  morning  and  in  the  evening  is  nearly  the  same,  but  the  influence 
of  these  factors  in  maintaining  this  pressure  is  reversed.  In  the 
morning  the  pressure  is  kept  at  the  normal  level  through  alterations 
in  the  tonicity  of  the  blood  vessels,  while  at  night,  on  account  of 
general  fatigue,  the  vasomotor  centre  is  no  longer  able  to  maintain 
the  tone  of  the  vessels,  and  only  by  an  increased  heart  rate  can  the 
pressure  be  kept  at  the  former  level.  Stewart3  has  further  shown 
that  the  output  of  the  heart  may  vary  greatly  with  a  constant  heart 
rate,  and  on  the  other  hand,  the  output  may  be  constant  with  a 
variable  pulse  rate.  It  is  evident,  therefore,  that  the  blood-pres- 
sure, in  normal  physiological  conditions,  is  a  resultant  of  the  com- 
bined action  of  these  two  factors.  With  increased  vaso-constriction 
of  the  peripheral  vessels  and  an  increased  heart  rate  there  should  be 
a  rise  in  the  arterial  pressure.  This  is  observed  in  conditions  of 
mental  and  muscular  activity,  while  in  such  conditions  as  rest  and 
sleep,  the  pulse  rate  being  slower  and  the  peripheral  vessels  dilated, 
the  resulting  phenomenon  is  lowered  blood-pressure. 

In  hypnotic  sleep,  as  was  stated  in  the  preceding  section,  these 
factors,  i.  e.,  vascular  tone  and  heart  rate  do  not  vary  in  the  same 
direction,  but  are  dissociated,  each  having  an  opposite  influence 
upon  the  blood-pressure.  Vaso-constriction  of  the  skin,  through 
the  increased  resistance  of  the  peripheral  vessels,  tends  to  raise  the 
general  arterial  pressure ;  while  on  the  other  hand,  the  slower  pulse 
rate  lowers  the  pressure,  the  result  in  general  being  an  irregular 
curve.  The  only  case  in  which  any  direct  similarity  can  be  traced 
between  the  course  of  the  pressure  curve  and  those  of  the  volume 

1  BIXET  and  COURTIER:    L'annee  psychologique,  1897.  iii,  p.  10. 

2  HILL:    Journal   of   physiology,    1895,   xviii,   p.    15:    1897-98,  xxii,  p.   xxvi ; 
1898-99,  xxiii,  p.  iv:  The  cerebral  circulation.  London,  1896. 

3  STEWART:  Journal  of  physiology,  1897-98,  xxii,  p.  159. 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      157 

changes  in  the  arm  and  changes  in  the  heart  rate,  was  in  the  ex- 
periment of  December  12,  1899,  in  which  the  general  course  of  the 
pulse  rate  and  the  blood-pressure  curves  was  the  same.  If  the 
changes  in  the  effect  of  the  heart  rate  and  the  vascular  tone  had 
been  constant,  the  blood-pressure  would  have  been  expressed  by 
the  algebraical  sum  of  the  two.  As  is  shown  by  a  comparison  of 
the  general  pressure  curve  with  the  curve  of  the  heart  rate  and  with 
the  plethysmographic  tracings,  the  course  of  the  pressure  curve, 
although  taking  the  general  direction  it  should  have  taken  if  the 
influence  of  these  factors  had  been  constant,  contains  many  irregu- 
larities which  are  due,  some  to  the  heart  rate  and  some  to  the 
vascular  tone,  as  the  influence  of  one  or  the  other  of  these  factors . 
prevails.  A  similar  relation  is  evident  from  a  study  of  the  curves 
for  each  experiment. 

Provided  the  assumption  is  correct  that  during  the  period  in 
which  the  hypnotic  suggestion  is  being  given  there  is  increased 
mental  activity,  there  should  be  a  rise  in  the  blood-pressure  at  this 
time.  It  cannot  be  definitely  stated  that  such  is  the  case,  since  no 
determinations  of  the  pressure  were  made  during  this  period.  In 
every  case,  with  the  exception  of  the  experiment  of  December  15, 
1899,  a  fall  in  the  pressure  was  observed  when  the  first  reading  for 
the  period  of  hypnotic  sleep  was  made.  As  the  pressure  tracing 
was  not  continuous,  the  readings  being  taken  but  once  in  fifteen 
minutes,  this  first  observation  occurred  several  minutes  after  the  sug- 
gestion had  been  given,  and  hence  the  pressure  may  have  been 
augmented  during  this  period  without  showing  any  effect  upon  the 
first  pressure  observation  taken  during  the  hypnotic  sleep.  The  fall 
noticed  at  this  time  corresponds  to  the  vascular  dilatation  and  to 
the  slower  .pulse  rate  occurring  during  the  first  part  of  hypnotic 
sleep.  The  course  of  the  plethysmographic  tracing  and  of  the 
curve  of  the  heart  rate,  during  hypnosis,  is  at  first  a  slow  fall, 
followed  by  a  steady  and  gradual  rise  until  the  end  of  the  sleep. 
This  explains  in  all  probability  the  general  line  of  the  blood-pres- 
sure curve,  since  it  follows  the  same  course.  The  great  variations 
noticed  on  the  pressure  curve  are  possibly  due  to  the  fact  that 
while  the  vasomotor  constriction  is  practically  constant  and  continu- 
ally increasing,  the  heart  rate  remains  below  the  normal  and  varies  to 
some  extent  irregularly;  the  pressure  might,  therefore,  show  con- 
siderable fluctuation,  according  as  these  factors  co-operated  or  varied 
in  opposite  directions. 


158  E.  C.  Walden. 

In  hypnotic  sleep,  therefore,  the  blood-pressure  depends  upon 
both  the  vaso-constriction  of  the  peripheral  vessels  and  upon  the  pulse 
rate,  the  pressure  being  above  or  below  the  normal  blood-pressure, 
according  as  the  vascular  tone  of  the  peripheral  vessels  or  the  heart 
rate  has  the  greater  influence. 


SUMMARY  AND  GENERAL  CONCLUSIONS. 

The  facts  observed  during  this  investigation  of  hypnotic  sleep  and 
the  explanations  suggested  may  be  summarized  as  follows: 

1.  On  suggesting  hypnotic  sleep  there  is  a  sudden,  comparatively 
short-lasting,  constriction  of  the  arm,  the  plethysmographic  tracing 
mounting  steadily  upward  until  the  act  of  suggestion  is  ended.     The 
diminution  in  the  volume  of  the  arm  is  probably  due  to  the  vaso- 
constriction  of  the  peripheral  vessels  of  the  arm,  the  reaction  being 
similar  to  that  known  to   be  produced  normally  by  sensory  stimuli 
leading  to  increased  psychical  activity. 

2.  When  the  act  of  suggestion  ends  there  is  a  fall  in  the  plethys- 
mographic tracing.     The  fall  differs  in  extent  and  in  duration  in  the 
different  experiments,  varying,  in  round  numbers,  from  one  to  thirty 
millimetres,  which  corresponds  to  a  volume  change  in  the  hand  and 
that  portion  of  the  fore-arm  within  the  plethysmograph  of  from  two- 
tenths  to  ten  cubic  centimetres  and  in  duration,  from  one  minute  to 
two  hours.     This  fall  in  the  curve  is  not  continuous  as  is  the  rise,  but 
is  broken  by  minor  variations,  in   all  probability  due  to  vasomotor 
excitation. 

3.  The  curve,  after  falling  for  a  variable  length  of  time,  gradually 
and  steadily  rises  during  several  hours,  and  continues  to  rise  until  the 
end  of  the  hypnotic  sleep.     This  portion  of  the  curve  is  irregularly 
interrupted  by  minor  oscillations  due  to  variations  in  vascular  tone. 
The  diminution  in  the  volume  of  the  hand  and  that  portion  of  the 
fore-arm  within    the  plethysmograph  in  many  of  the    experiments 
amounted  to  thirty  cubic   centimetres.     The  rise  is  undoubtedly  due 
to  a  vaso-constriction  of  the  peripheral  vessels. 

4.  At  the  instant  the  sleeper  is  awakened  there  is  a  sudden,  but 
brief,  rise  in  the  curve,  corresponding  to  a  greater  constriction  of  the 
peripheral  vessels;   this   constriction  often  amounted  to  a  change  in 
the   volume  of  the    hand  and  fore-arm  of  eight  cubic  centimetres. 
This  change  in  all  probability  is  due  to  the  action  of   mental  and 
sensory  stimuli  upon  the  vasomotor  centre  during  the  act  of  awaken- 


Study  of  Vasc^tlar  Conditions  during  Hypnotic  Sleep.      159 

ing.  After  this  brief  rise,  caused  by  the  stimulus  of  awakening,  the 
curve  rapidly  falls  until  the  tracing  has  reached  about  the  level  it  had 
before  the  suggestion  of  hypnotic  sleep  was  given. 

5.  Immediately  following  the  act  of  suggestion,  there  is  a  fall  in  the 
arterial    blood-pressure  as    measured    in    the    fingers,  which  on  the 
average  amounts  to  seven  millimetres  of  mercury.     During  the  period 
of  hypnotic  sleep  the  pressure  flutters  about  the  normal  level;   the 
tendency  during   the  first  part  of  the  sleep  is  for   the  pressure  to 
remain  below  the  normal,  and  during  the  remainder  of  the  experiment 
to  gradually  increase,  often  rising  above  the  normal  level.     On  wak- 
ing, there  is  always  a  sudden  rise  in  the  pressure,  the  pressure  increas- 
ing as  much  as  fifteen  millimetres  of  mercury.     The  gradual  rise  in 
the  pressure  toward  the  end  of  the  period  of  hypnotic  sleep  is,  on  the 
whole,  parallel  with  the  increased  vaso-constriction  of  the  peripheral 
vessels  and  the  increasing  pulse  observed  during  the  same  period. 

6.  The  pulse  rate  is  slower  during  hypnotic  sleep  than  before  or 
after  that  period.     The  heart  beats  less  rapidly  during  the  first  part 
of  hypnotic  sleep  than  later  in  the  period.     On  waking  the  pulse  is 
accelerated,  the  heart  beating  more  rapidly  than  at  any  other  time 
during  the  experiment.     This  more  rapid  pulse  rate  continues  for  a 
considerable  period,  from  fifteen  to  twenty  minutes,  after  the  subject 
is  entirely  awake. 

7.  During  hypnosis  the  respiratory  rate  is  slower  than  during  the 
normal  waking   state.      The    respiration  is   slower  during  the   first 
portion    of  hypnotic   sleep    than   later   in    the    period.      When    the 
sleep  continues  for  several  hours,  the  respirations  may  be  even  more 
rapid  than  they  were  before  the  suggestion  was  given.     On  waking 
the  subject,  the  respiratory  rate  is  increased,  the  rate  being   more 
rapid  than  at  any  other  time  during  the  experiment. 

8.  There  is  a  steady  although  a  very  slight  fall  in  the  rectal  tem- 
perature during  hypnotic  sleep.     The  greatest  change  in  the  rectal 
temperature  recorded  in  an  experiment  was  but  four-tenths  of  one 
degree.     On  waking,  the  rectal  temperature  rises  slightly,  but  it  does 
not  return  to  the  height  it  had  previous  to  the  suggestion. 

9.  The  surface  temperature  of  the  arms  is  higher  during  hypnotic 
sleep  than  at  the  beginning  of  the  experiment.     The  temperature 
gradually  rises  during  the  first  hour  of  hypnotic  sleep,  this  increase 
amounting  to  about  six-tenths  of  one  degree.     This  rise  is  followed 
by  a  slower  and  more  gradual  fall,  which  lasts  until  the  end  of  the 
hypnotic  sleep  and   amounts  to  about  eight-tenths   of  one   degree. 


160  E.  C.  Walden. 

On  waking,  the  temperature  rapidly  increases,  reaching  a  point  much 
higher  than  at  any  other  time  during  the  experiment. 

10.  On  giving  an  hypnotic  suggestion  to  a  subject  during  the 
waking  state,  there  is  a  rise  in  the  plethysmographic  tracing,  the  rise 
lasting  as  long  as  the  suggestion  continues.  As  soon  as  the  sugges- 
tion is  ended,  the  tracing  sinks  to  about  the  level  it  had  previous 
to  the  suggestion,  the  effect  corresponding  to  that  of  an  ordinary 
mental  stimulation.  The  fall  at  the  end  of  the  suggestion  is  not  so 
rapid  as  the  previous  rise.  If  during  hypnotic  sleep  a  suggestion  is 
given,  the  effect  upon  the  curve  is  different.  At  the  moment  the 
suggestion  is  begun,  there  is  a  sharp  rise  in  the  curve ;  this  rise 
amounts  to  but  one  or  two  millimetres  and  is  only  momentary.  The 
curve  then  sinks  rapidly  until  the  end  of  the  suggestion,  after 
which  it  rises  to  about  the  level  it  had  before  the  suggestion 
was  given.  The  fall  in  the  curve,  as  the  result  of  the  suggestion, 
amounts  in  round  numbers  to  about  ten  millimetres,  which  corre- 
sponds to  a  change  in  the  volume  of  the  hand  and  that  portion  of 
the  fore-arm  within  the  plethysmograp'  of  three  cubic  centimetres. 
The  fall  in  the  curve  as  the  result  of  suggestion  during  hypnotic 
sleep  is  in  all  probability  due  to  a  partial  awakening  of  the  subject, 
since  the  small  rise  and  the  subsequent  fall  noticed  in  these  cases 
are  the  same  as  those  observed  when  the  subject  is  awakened  from 
hypnotic  sleep.  The  rise  occurring  at  the  end  of  the  suggestion  is 
probably  due  to  the  return  of  the  deeper  hypnotic  condition. 

It  is  difficult  to  draw  any  general  conclusions  as  to  the  bearing  of 
these  facts  upon  the  theories  of  the  cause  of  hypnotic  sleep.  The 
pronounced  and  increasing  vaso-constriction  in  the  arm  during  most 
of  the  period  of  sleep,  for  the  time  at  least  that  these  experiments 
lasted,  is  perhaps  the  most  positive  and  suggestive  result  obtained. 
It  is  in  general  the  reverse  of  the  condition  observed  in  natural  sleep. 

In  the  latter  condition  the  peripheral  dilatation,  the  slower  heart 
beat,  and  the  lower  general  blood-pressure  make  it  probable  that 
less  blood  flows  to  the  brain.  In  hypnotic  sleep  the  peripheral  con- 
striction might  suggest  the  reverse,  namely,  a  greater  flow  of  blood 
to  the  brain.  However  this  conclusion  is  not  entirely  supported 
by  the  observations  on  blood-pressure.  This  latter  varied  irregu- 
larly, according  to  the  observations  made,  and  although  its  general 
curve  may  be  considered  as  substantially  parallel  to  the  volume 
changes  in  the  arm,  nevertheless  its  absolute  value  was  not  materi- 
ally increased  above  the  normal  before  the  experiment  began.  The 


Study  of  Vascular  Conditions  during  Hypnotic  Sleep.      161 

difficulty  here  seems  to  have  been  that  whereas  in  normal  sleep 
the  peripheral  dilatation  and  lower  pulse  rate  co-operate  to  lower 
general  blood-pressure,  in  the  hypnotic  sleep  the  peripheral  con- 
striction is  antagonized,  so  far  as  its  effect  on  blood-pressure  is  con- 
cerned, by  the  lower  heart  rate.  One  general  conclusion  seems  to 
be  permissible.  Assuming,  as  there  is  good  reason  for  doing,  that 
lessening  of  mental  activity  is  accompanied  by  a  peripheral  dilatation 
of  the  blood  vessels,  particularly  perhaps  in  the  skin,  and  that 
increased  psychical  activity  is  accompanied  by  the  reverse  condi- 
tion of  a  peripheral  constriction,  then  the  remarkable  general 
tendency  to  a  peripheral  constriction  during  hypnotic  sleep,  except 
for  a  variable  initial  period,  would  point  to  a  steadily  acting  mental 
stimulation  during  the  time  that  the  suggestion  is  effective. 

I  desire  to  acknowledge  my  great  indebtedness  to  Professor  W.  H. 
Howell  for  the  constant  aid  and  valuable  advice,  which  have  made 
these  experiments  possible,  and  to  express  my  thanks  to  him  and  to 
the  other  members  of  the  Physiological  Staff  of  the  Johns  Hopkins 
University  for  their  interest  in  the  progress  of  the  investigation. 
I  also  wish  to  thank  especially  Mr.  H.  M.  Steele  and  Miss  Anna  G. 
Lyle,  who  have  hypnotized  the  subjects  upon  whom  the  experiments 
were  made,  and  have  also  assisted  in  making  the  observations. 


BIOGRAPHICAL  SKETCH. 

ELISHA  CHISHOLM  WALDKN  was  born  in  Chicago,  Illinois,  Novem- 
ber 24,  1871.  His  primary  education  was  received  in  the  public 
schools  of  Cincinnati,  Ohio,  and  Covington,  Kentucky.  He  prepared 
for  college  in  the  Academic  Department  of  the  U.  S.  Grant  University, 
Chattanooga,  Tennessee.  After  a  four  year's  course  he  received  the 
degree  of  Bachelor  of  Arts  from  the  Ohio  Wesleyan  University  in 
1892.  During  the  scholastic  year  of  1892-1893  he  pursued  a  course 
in  Chemistry  in  the  Cincinnati  University.  From  1893-1895  he 
occupied  the  chair  of  Natural  Science  in  Rust  University,  Holly 
Springs,  Mississippi.  In  the  fall  of  1895  he  entered  the  University 
of  Chicago  as  a  post-graduate  student  in  Biology.  He  was  appointed 
Fellow  in  Biology  in  the  Cincinnati  University  for  the  scholastic  year 
1896-1897,  and  he  received  the  degree  Master  of  Science  in  June, 
1897,  from  this  University.  He  entered  the  Johns  Hopkins  Univer- 
sity in  1897  as  a  candidate  for  the  degree  of  Doctor  of  Philosophy. 
He  selected  as  his  principal  subject,  Physiology,  and  for  his  subor- 
dinate subjects,  Pathology  and  Chemistry. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


MflY  1  3  1953 
MAR  2  3  1959 


MAY  1  9  «P 

*— ~ ' 

C'DLD 

MAY  13  1960 


P41S- 


